8. The Quick Draw Problem

6 Jun
maths with zombies

…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.


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