12. The Prius Vs SUV Problem

…because everything’s better with zombies!

The dead have risen and you want to get as far away as quickly as possible. You run out your house to look for some transport. You can only find two possible cars: an SUV with its 42 gallon fuel tank two-thirds full and a Prius with 9 gallons of fuel in it. The SUV does 14 mpg (miles per gallon) while the Prius does 36 mpg. Which vehicle will allow you to get further away from the zombie outbreak?

A: I’d take the SUV, it uses more gas per mile, but with all that fuel in the tank, it’ll get you further.

B: I’d take the Prius. There’s less fuel in it but it does more miles to the gallon and that will mean I can get further away.

Scroll down to see the right answer…

What answer did you get?

A: You made the right choice. Despite the fact that it’s less fuel efficient, given the amount of fuel in its tank, you will be able to get further before you run out.

B: While it might be a good choice for the environment, the Prius is a poor choice in this case. While the Prius is more efficient, meaning it can get further per gallon of fuel, the total distance you can drive is less than the SUV.

How to work it out: First you need to work out how far you can drive in the SUV. To do this, you begin by working out how much fuel it has in its fuel tank. The tank can hold 42 gallons when it’s full. If it is currently two-thirds full, it will contain two-thirds of 42 gallons. To work out how much this is, divide 42 by 3 and then multiply the answer by 2. This tells you there’s 28 gallons of fuel in the SUV’s tank. It does 14 miles per gallon, so if you multiply the amount of fuel in its tank (28 gallons) by this number, you will know how far it can travel. In this case, it’s 392 miles. Next, you move onto the Prius. Here, you already know the amount of fuel in the tank (9 gallons), so all you need to do is multiply this number by the number of miles it can do per gallon (36). This gives you 324. So despite its better fuel efficiency, the Prius will only get you 324 miles away from the zombie outbreak, while the SUV will get you 392 miles. That’s another 68 miles the zombies need to travel to get you, and in a zombie apocalypse that could be the difference between living and dying!

Note: While the problems provided here are copyright of Maths With Zombies, if you are a teacher, you can use any of these problems for free in your classes – but please credit Maths With Zombies as the original source (e.g. Downloaded from MathsWithZombies.wordpress.com). You can download a PDF handout of this problem from here.

If you do use this problem in a class, please post a comment here to let me know how you used it and how it was received by your students. These problems cannot be used for any commercial purpose without express written permission.

*****************************************************************************

From the author of For Those In Peril On The Sea, a tale of post-apocalyptic survival in a world where zombie-like infected rule the land and all the last few human survivors can do is stay on their boats and try to survive. Now available in print and as a Kindle ebook. Click here or visit www.forthoseinperil.net to find out more. To download a preview of the first three chapters, click here.

To read the Foreword Clarion Review of For Those In Peril On The Sea (where it scored five stars out of five) click here.

11. The Fork In The Road Problem

…because everything’s better with zombies!

You’ve been caught out in the open while you were foraging for food. You are at a fork in the road, with the zombies coming from the south and they are 100 yards away from you. You have two options both of which lead to a safe house. On the road to the northeast, the safe house is only a 100 yards away but it’s up a steep hill. To the northwest, the safe house is further away (some 300 yards) but it’s all downhill. You know you can run at 11.25 miles an hour downhill but only 7.5 miles an hour uphill. The zombies are relentless and can move at 15 miles an hour regardless of whether it’s uphill or downhill. Which way should you go? (Hint: There’s 1,760 yards in a mile).

A: I’d go northwest, it’s further but I can run faster downhill so I’d get there quicker.

B: I’d go northeast. The safe house is nearer so even though I can run slower uphill, I’d get there quicker.

C: It doesn’t matter which way I go, I’ll always make it to a safe house first as long as I don’t waste time trying to work out which way I should go.

D: It doesn’t matter which way I go, given how fast the zombies can run they’ll always get me before I reach a safe house.

E: It will be a dead heat. We’ll all reach the door at the same time but that doesn’t matter because I’ll still end up dead – in the case of a draw, the zombies will always win!

Scroll down to see the right answer…

What answer did you get?

A: Unlucky, the zombies will arrive at the northwest safe house at the same time you did, and this meant they’ll eat you before you get inside.

B: Unlucky, the zombies will arrive at the northeast safe house at the same time you did, and this meant they’ll eat you before you get inside.

C: Something went wrong with your maths there, you can’t make it to either safe house before the zombies get to you.

D: You’re right that it doesn’t matter which safe house you head for, but your maths seems to have gone wrong because you’ll reach the safe house at the same time as the zombies.

E: Spot on! You got the maths right, but that’s not going to be much consolation to you. Since you’ll all arrive at the safe house at the same time, you won’t have time to get inside so you’ll end up dead despite the fact you got the maths right.

How to work it out: You need to work out four things: how long it will take you to each safe house, and then how long it will take the zombies to reach each safe house. In all cases, the maths is the same. First you work out the distance you need to cover and then divide this by the speed. For example, for you to get to the safe house to the northeast, you need to cover 100 yards, but your speed is only 7.5 miles an hour. First convert the speed from miles and hour to yards an a second. This is done by multiplying the speed by the number of yards in mile (1,760) and then dividing it by the number of seconds in an hour (3,600). By doing this, you can work out that 5 miles an hour is the same as 3.67 yards a second. You then divide the distance you need to cover (100 yards in this case) by this number, and you find you’ll reach the northeast safe house in 27.27 seconds. When you do this for the other safe house, you’ll find it’ll also take you 54.55 seconds to reach it. The zombies have to travel further (200 yards to the northeast safe house and 400 yards to the northwest safe house), but they can also move faster. Travelling at 15 miles per hour, it will take then 27.27 to reach the nearer safe house and 54.55 to reach the one that’s further away This means that no matter which way you go, you and the zombies will both reach the door of your chosen safe house at the same time. You’re pretty much screwed either way!

Note: While the problems provided here are copyright of Maths With Zombies, if you are a teacher, you can use any of these problems for free in your classes – but please credit Maths With Zombies as the original source (e.g. Downloaded from MathsWithZombies.wordpress.com). You can download a PDF handout of this problem from here.

If you do use this problem in a class, please post a comment here to let me know how you used it and how it was received by your students. These problems cannot be used for any commercial purpose without express written permission.

*****************************************************************************

From the author of For Those In Peril On The Sea, a tale of post-apocalyptic survival in a world where zombie-like infected rule the land and all the last few human survivors can do is stay on their boats and try to survive. Now available in print and as a Kindle ebook. Click here or visit www.forthoseinperil.net to find out more. To download a preview of the first three chapters, click here.

To read the Foreword Clarion Review of For Those In Peril On The Sea (where it scored five stars out of five) click here.

10. The Disappearing Zombies Problem

…because everything’s better with zombies!

The apocalypse has come and, with the exception of a few small, scattered groups of survivors, the entire population of the world has been turned into zombies. That means there’s 7 billion undead walking around, looking for human flesh to feast on. You’re lucky enough to be holed up in an old military bunker you stumbled upon while escaping from the city. You know that zombies, being re-animated dead bodies, will eventually rot away, making it safe for you to go outside again. You work out that zombies have a half-life of 28 days. This means that every 28 days the number of zombies will decrease by 50%. How long will be before all the zombies are gone and it’s safe for you to go outside again?

A: 364 days.

B: 756 days.

C: 924 days.

D: 1,120 days.

Scroll down to see the right answer…

What answer did you get?

A: Something when wrong with your maths there. There will still be more than a million zombies left and you’ll probably get eaten!

B: That’s a bit too soon. You might get away with it, but there will still be a few zombies wandering around out there.

C: Spot on! The last of the zombies will have rotted away just as you step through the door into the outside world.

D: You’ve got that wrong. You’ll still be huddled in your bunker as all the other survivors are out there staking their claims and re-building civilisation.

How to work it out: The starting point here is 7 billion (the number of zombies in the world when you enter the bunker). To work out how many zombies there’ll be after 28 days, you divide this number by 2. This is 3.5 billion (which is still a lot). After another 28 days, this number will be halved again (giving 1.75 billion). You then repeat this until you get a number that’s less than 1. You will need to do this a total of 33 times. This means that it’ll take 924 days (28 * 33) before the last zombie will have disappeared. That’s 2 years, 6 months, and 13 days (I hope you brought a good book with you!).

Note: While the problems provided here are copyright of Maths With Zombies, if you are a teacher, you can use any of these problems for free in your classes – but please credit Maths With Zombies as the original source (e.g. Downloaded from MathsWithZombies.wordpress.com). You can download a PDF handout of this problem from here. If you do use this problem in a class, please post a comment here to let me know how you used it and how it was received by your students. These problems cannot be used for any commercial purpose without express written permission.

*****************************************************************************

From the author of For Those In Peril On The Sea, a tale of post-apocalyptic survival in a world where zombie-like infected rule the land and all the last few human survivors can do is stay on their boats and try to survive. Now available in print and as a Kindle ebook. Click here or visit www.forthoseinperil.net to find out more. To download a preview of the first three chapters, click here.

To read the Foreword Clarion Review of For Those In Peril On The Sea (where it scored five stars out of five) click here.

9. The Food Supply Problem

…because everything’s better with zombies!

The zombie apocalypse has come and you find yourself all alone and barricaded into an old house. You don’t know who lived there before but they kept their cupboards well stocked. You count everything that’s in them and find you’ve got 56 cans of food. Unfortunately, they’re all spam but it’s better than nothing. You read the label and find that each can weighs 200g and contains 621 calories. You know you need eat 2,500 calories each day to stay healthy. How many days can you survive on your spam before you have to go outside, where the zombies are, in search of food?

A: 13 days.

B: 15 days.

C: 17 days.

D: 19 days.

Scroll down to see the right answer…

What answer did you get?

A: Spot on, but I’m betting that after almost two weeks, you’ll never want to taste another piece of spam as long as you live!

B: You’re a bit over there and you’ll run out of food a couple of days before you think you will.

C: It might be spam, but it’s not going to last that long.

D: You’re out by almost a quarter. If a zombie apocalypse ever comes maybe you’d better leave someone else in charge of the food supplies!

How to work it out: Firstly, don’t get confused by the information about the weight of each can, you don’t need to know this to work out the answer. Instead, you only need to know the number of calories each can has in it (621). You have a total of 56 cans, and each can contains 621 calories. If you multiply these two numbers together (so that’s 56 * 621), you get the total number of calories contained in all the cans (in this case it’s 34,776). You then divide this number by the number of calories you need to each day (so that’s 34,776 divided by 2,500) and this gives you the number of days the food will last for. In this case it’s 13.9, so sometime on the evening of the 13th day, you’re going to finally run out of food. After that, you’ll have no choice but to go outside to look for more.

Note: While the problems provided here are copyright of Maths With Zombies, if you are a teacher, you can use any of these problems for free in your classes – but please credit Maths With Zombies as the original source (e.g. Downloaded from MathsWithZombies.wordpress.com). You can download a PDF handout of this problem from here. If you do use this problem in a class, please post a comment here to let me know how you used it and how it was received by your students. These problems cannot be used for any commercial purpose without express written permission.

*****************************************************************************

From the author of For Those In Peril On The Sea, a tale of post-apocalyptic survival in a world where zombie-like infected rule the land and all the last few human survivors can do is stay on their boats and try to survive. Now available in print and as a Kindle ebook. Click here or visit www.forthoseinperil.net to find out more. To download a preview of the first three chapters, click here.

To read the Foreword Clarion Review of For Those In Peril On The Sea (where it scored five stars out of five) click here.

8. The Quick Draw Problem

…because everything’s better with zombies!

You’re on your own in a dark alley when a zombie suddenly spots you. It turns in your direction and charges towards you. It’s twenty feet away and, since it’s one of those pesky new fast zombies, it’s moving at a speed of nine miles an hour. You know it will take you 1.5 seconds flat to draw your gun, aim and fire. Will you have time to kill the zombie before it gets to you? (Hint: There’s 5,280 feet in a mile.)

A: There isn’t enough time to shoot the zombie, I’d better start running.

B: I’ve got enough time so I should stand my ground and kill the zombie.

Scroll down to see the right answer…

What answer did you get?

A: You’d have had enough time so you could have shot the zombie. You might have got the maths wrong, but at least you’re still alive.

B: You made the right decision and now there’s one less flesh-muncher in the world – only another six billion to go!

How to work it out: The zombie is travelling at 9 miles an hour but you need to know how long it will take to cover 20 feet. The first thing you need to do is convert the speed from miles an hour to feet per hour. This is 9 times the number of feet in a mile (5,280) which is 47,520. It’s only got to travel 20 feet to get to you. If you divide the distance it has to cover (20 feet) number by the number of feet it can travel in an hour (47,520), this will tell you how long it will take to cover this distance. In this case it’s 0.0004209. This figure seems odd, but this is because this is the length of time in hours it will take to travel 20 feet. To convert this number into seconds, you need to multiply it by 3,600 (the number of seconds in an hour). This tells you that at 9 miles an hour the zombie will take 1.51524 seconds to reach you. Since you can draw you gun, aim and fire in 1.5 seconds flat, you’ll be able to get your shot off just a fraction of a second before it gets to you. You’d better not miss though, because you’ll only have one chance to kill it before it gets to you!

Note: While the problems provided here are copyright of Maths With Zombies, if you are a teacher, you can use any of these problems for free in your classes – but please credit Maths With Zombies as the original source (e.g. Downloaded from MathsWithZombies.wordpress.com). You can download a PDF handout of this problem from here. If you do use this problem in a class, please post a comment here to let me know how you used it and how it was received by your students. These problems cannot be used for any commercial purpose without express written permission.

*****************************************************************************

From the author of For Those In Peril On The Sea, a tale of post-apocalyptic survival in a world where zombie-like infected rule the land and all the last few human survivors can do is stay on their boats and try to survive. Now available in print and as a Kindle ebook. Click here or visit www.forthoseinperil.net to find out more. To download a preview of the first three chapters, click here.

To read the Foreword Clarion Review of For Those In Peril On The Sea (where it scored five stars out of five) click here.

7. The Rapid Fire Problem

…because everything’s better with zombies!

You are armed with a machine gun that can fire 131 bullets per minute; that’s a lot of bullets but it’s not very accurate and you only hit 30% of the zombies you fire at. Suddenly a swarm of 400 zombies appears over a nearby hill and they’re moving quickly (they’re these pesky new fast zombies!). You estimate they’ll at the door to your compound in 10 minutes and if that happens you’ll be over-run. Is there enough time to kill all the zombies with your machine gun before they get there? If there is your best option is to stand and fight. If not, you should run now. You’ll have to leave all your supplies and gear behind and start afresh somewhere new; it won’t be easy, but at least you’ll be alive!

A: I’ll get them all just in time, my best option is to stay and fight.

B:There’s not enough time to kill all the zombies before they get here. I need to get out now.

Scroll down to see the right answer…

What answer did you get?

A: Uh-oh, something when wrong with your calculations. You should have turned and run; instead you’ll end up as zombie chow.

B: Well done, you got the maths right and you’ll live to fight another day. You must have worked out that you’ll only kill 393 of the 400 zombies by the time they get to you.

How to work it out: The machine gun can fire 131 bullets a minute. If you multiply this by the length of time you have to kill all the zombies (10 minutes), you’ll find that you can fire 1,310 bullets in that length of time. That would be more than enough bullets if it wasn’t for the lack of accuracy. The gun is only 30% accurate. When expressed as a probability, this is 0.3. This means that for every 10 shots fired, you’ll only kill three zombies. If you multiply the number of bullets you can fire in 10 minutes (1,310) by probability of each bullet killing a zombie (0.3), you’ll find that despite firing over 1,000 bullets, you’ll only kill 393 zombies. This means there will be 7 left to over-run your defences.

Note: While the problems provided here are copyright of Maths With Zombies, if you are a teacher, you can use any of these problems for free in your classes – but please credit Maths With Zombies as the original source (e.g. Downloaded from MathsWithZombies.wordpress.com). You can download a PDF handout of this problem from here. If you do use this problem in a class, please post a comment here to let me know how you used it and how it was received by your students. These problems cannot be used for any commercial purpose without express written permission.

*****************************************************************************

From the author of For Those In Peril On The Sea, a tale of post-apocalyptic survival in a world where zombie-like infected rule the land and all the last few human survivors can do is stay on their boats and try to survive. Now available in print and as a Kindle ebook. Click here or visit www.forthoseinperil.net to find out more. To download a preview of the first three chapters, click here.

To read the Foreword Clarion Review of For Those In Peril On The Sea (where it scored five stars out of five) click here.

6. The Injured Friend Problem

…because everything’s better with zombies!

You can see the zombies coming towards you. You estimate that they’re moving at about 4 miles an hour. Normally you’d be able to out run them no problem but today your carrying your best friend who’s just broken his leg and can’t walk. This means you can only move at 1 miles an hour (he might be your friend but he’s heavy!). You can see the door to your safe house at the end of the street. It’s 83 yards away. You look back over your shoulder, the zombies are 250 yards behind you. You have two options: You can carry on with your friend but he’ll slow you down or you can abandon him so you can move faster. Will you still make it to your safe house before the zombies get there? (hint: There’s 1,760 yards in a mile).

A: Yes, so the best thing to do is keep carrying my friend.

B: No, so the only way I’ll survive is if I abandon my friend so I can run faster.

Scroll down to see the right answer…

What answer did you get?

A: You got it right. You’ll arrive at the safe house just half a second before the zombies. Just as well you didn’t get it wrong and accidentally go for B.

B: Oh no! You got your maths wrong and now your friends being eaten alive by zombies when you could have made it even without abandoning him. You did get the maths wrong didn’t you? You didn’t just abandon him, did you? Humm, I’m not too sure I trust you any more …

How to work it out: First, the zombies to reach the safe house: They can travel at 4 miles an hour, that’s 7,040 yards (4 * 1760 or the number of yards in a mile). This means they will cover the 333 yards to the safe house (the 83 yards between you and the safe house plus the 200 yards between you and the zombies) in 0.0473 hours. This is worked out by dividing the distance they need to cover (283 yards) by the distance they can travel in an hour (7,040 yards). 0.0473 hours is the equivalent of 2 minutes and 50.3 seconds. You’ve only got 83 yards to cover but you’re moving much slower. You can only cover one mile or 1,760 yards in an hour. You will take 0.0472 hours (83/1,760) to reach the safe house. That’s 2 minutes and 49.8 second meaning you’ll reach safety with just a hair over half a second. If you’d been just one more yard further from the safe house, they’d have got you.

Note: While the problems provided here are copyright of Maths With Zombies, if you are a teacher, you can use any of these problems for free in your classes – but please credit Maths With Zombies as the original source (e.g. Downloaded from MathsWithZombies.wordpress.com). You can download a PDF handout of this problem from here. If you do use this problem in a class, please post a comment here to let me know how you used it and how it was received by your students. These problems cannot be used for any commercial purpose without express written permission.

*****************************************************************************

From the author of For Those In Peril On The Sea, a tale of post-apocalyptic survival in a world where zombie-like infected rule the land and all the last few human survivors can do is stay on their boats and try to survive. Now available in print and as a Kindle ebook. Click here or visit www.forthoseinperil.net to find out more. To download a preview of the first three chapters, click here.

To read the Foreword Clarion Review of For Those In Peril On The Sea (where it scored five stars out of five) click here.

5. The Hungry Zombies Problem

…because everything’s better with zombies!

There’s five million people in your city and 25 graveyards. Each graveyard has 5,000 graves in it and when the zombie apocalypse comes the dead in all these graves will rise up and attack the living. How many people will each zombie have to consume before there’s no one left?

A: 10.

B: 40.

C: 100.

D: 400.

Scroll down to see the right answer…

What answer did you get?

A: That would barely make a dent in the human population of the city. There’d still be 3.75 million people left.

B: You’re right, but it’s not a lot that each zombie needs to eat to consume a whole city, is it?

C: That’s a lot of people for each zombie to eat. At that rate, they’d be able to devour two and a half cities.

D: If each zombie ate that many, they’d be able to consume ten cities worth of people, not just one!

How to work it out: First, you need to work out how many zombies there will be. This is done by multiplying the number of graves in each graveyard (5,000) by the number of graveyards in the city (25). This gives tells you that there’s 125,000 graves, and that means there will be 125,000 zombies when the dead start to rise. The average number of people each zombie needs to devour is then calculated by dividing the population size of the city (5,000,000) by the number of zombies (125,000). When you do this, you get 40. This means each zombie will have to consume 40 people before the entire city is devoured.

Note: While the problems provided here are copyright of Maths With Zombies, if you are a teacher, you can use any of these problems for free in your classes – but please credit Maths With Zombies as the original source (e.g. Downloaded from MathsWithZombies.wordpress.com). You can download a PDF handout of this problem from here. If you do use this problem in a class, please post a comment here to let me know how you used it and how it was received by your students. These problems cannot be used for any commercial purpose without express written permission.

*****************************************************************************
From the author of For Those In Peril On The Sea, a tale of post-apocalyptic survival in a world where zombie-like infected rule the land and all the last few human survivors can do is stay on their boats and try to survive. Now available in print and as a Kindle ebook. Click here or visit www.forthoseinperil.net to find out more. To download a preview of the first three chapters, click here.

To read the Foreword Clarion Review of For Those In Peril On The Sea (where it scored five stars out of five) click here.

4. The Viral Spread Problem

…because everything’s better with zombies!

There’s a virus turning people into zombies who attack the living and never die. No one knows where it came from but the first person (known as ‘patient zero’ by those who study how diseases spread) was an archaeologist who’d just discovered an ancient tomb so it might have come from there. The virus is spread when infected people bite someone who’s uninfected. If each zombie bites an average of three uninfected people each day, how long will it take before the entire human population of the planet (which for this problem will be taken as 7 billion people) are turned into shambling undead flesh-munchers?

A: 167 days (almost 6 months).

B: 53 days (just under 8 weeks).

C: 17 days (just over two week).

D: 6 days (less than a week).

Scroll down to see the right answer…

What answer did you get?

A: You’re way off! You’ll have no chance of stopping an outbreak if you can’t work out how fast it will spread.

B: You’re closer but you’re still dangerously under-estimating how fast the disease will spread.

C: Spot on! Now you know exactly how long it will take before humanity is gone.

D: You’re a pessimist aren’t you? The last human won’t become infected for another 11 days.

How to work it out:The simplest way to work it out is to calculate the number of people infected at the end of each day given the number of people infected at the start and the average number of people they will bite, and so infect. For day one, there will be one person infected at the start of the day (the unfortunate archaeologist) and he will infect three people by biting them. This means that at the end of the day there will be 4 zombies (1 + 3 = 4). Day two starts with 4 infected people, each of which will bite and infect three people. That’s a total of 12 people (4 * 3 = 12). At the end of day two there will be a total of 16 zombies (4 + 12 = 16). If we carry this on, we’ll find that at the end of day three there will be 64 zombies, 256 at the end of day 4 and so on, until at the start of day 17 there will be 4,294,967,296 zombies, and since there’s only 7 billion people on the planet, they will run out of uninfected people to bite somewhere around lunch time.

Note: While the problems provided here are copyright of Maths With Zombies, if you are a teacher, you can use any of these problems for free in your classes – but please credit Maths With Zombies as the original source (e.g. Downloaded from MathsWithZombies.wordpress.com). You can download a PDF handout of this problem from here. If you do use this problem in a class, please post a comment here to let me know how you used it and how it was received by your students. These problems cannot be used for any commercial purpose without express written permission.

*****************************************************************************
From the author of For Those In Peril On The Sea, a tale of post-apocalyptic survival in a world where zombie-like infected rule the land and all the last few human survivors can do is stay on their boats and try to survive. Now available in print and as a Kindle ebook. Click here or visit www.forthoseinperil.net to find out more. To download a preview of the first three chapters, click here.

To read the Foreword Clarion Review of For Those In Peril On The Sea (where it scored five stars out of five) click here.

3. The Fuel Crisis Problem

…because everything’s better with zombies!

You hear the first reports on the news that the dead have started to rise and attack the living. You knew this was going to happen and you’re ready. You grab your ‘bug out bag’ and a baseball bat before leaping into your car. The safe house you’ve been carefully preparing and provisioning for the last year is 74 miles away and if you drive fast enough you’ll be there in an hour at the most; then you’ll be safe. As you start your engine you glance at the fuel gauge and realise your room mate’s not only borrowed your car yet again without asking, but he’s also not topped up the tank so it’s only a quarter full. You know your tank holds 11 gallons when it’s full and your car does 27 miles to the gallon. What do you do?

A:I’ve got enough fuel to get there, so I’m leaving the city while I still can.

B:There’s not enough fuel left in the tank. I’ll need to get some more before I head off. It’ll be risky but at least I won’t end up stranded in the middle of nowhere when I run out.

Scroll down to see the right answer…

What answer did you get?

A: Well done, you made the right decision. You must have correctly worked out you have enough fuel to go 74.25 miles before you run out and that’s just enough to get you to your safe house.

B: Oooh, poor choice. You have enough fuel so you should leave immediately. Enjoy fighting off the zombie horde as you waste time trying to find more fuel.

How to work it out: You first need to work out how much fuel you have left in the tank. This is the size of the tank (11 gallons) divided by how much is left in it (1/4) and is 2.75 gallons. Next you need to work out how far you can go on this much fuel. This is done by multiplying the number of miles your car can do per gallon (27) by the amount of fuel you have left (2.75 gallons). This gives you 74.25 miles. Finally, subtract the miles you have to travel from this distance (74.25 – 74). If this number is positive ( as in this case where it’s 0.25), you’ve got enough fuel to get you there. If it’s negative, you haven’t. This would be the case if the miles per gallon was only 0.5 lower: (2.75 * 26.5) – 74 = -1.125, so you’d run out of fuel just over a mile from your safe house. If that were the case, you’d be better selecting option B.

Note: While the problems provided here are copyright of Maths With Zombies, if you are a teacher, you can use any of these problems for free in your classes – but please credit Maths With Zombies as the original source (e.g. Downloaded from MathsWithZombies.wordpress.com). You can download a PDF handout of this problem from here. If you do use this problem in a class, please post a comment here to let me know how you used it and how it was received by your students. These problems cannot be used for any commercial purpose without express written permission.

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From the author of For Those In Peril On The Sea, a tale of post-apocalyptic survival in a world where zombie-like infected rule the land and all the last few human survivors can do is stay on their boats and try to survive. Now available in print and as a Kindle ebook. Click here or visit www.forthoseinperil.net to find out more. To download a preview of the first three chapters, click here.

To read the Foreword Clarion Review of For Those In Peril On The Sea (where it scored five stars out of five) click here.