5. The Hungry Zombies Problem

16 May
maths with zombies

…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.


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