1. The Reload Problem

18 Apr
maths with zombies

…because everything’s better with zombies!

There are fifty zombies staggering towards you. You have a gun that holds six bullets and it’s fully loaded (after all there’s zombies out there so you’ll make sure you’re prepared before stepping out of your safe house). Assuming you don’t miss with any of your shots (and you’d better not or they’ll get you!), how many times will you have to reload your gun before you’ve kill all of them?

A: 6.

B: 7.

C: 8.

D: 9.

Scroll down to see the right answer…

What answer did you get?

A: That’s not nearly enough there’s still going to be loads of zombies coming at you.

B: You’re getting closer but there’s still be two dead men walking.

C: Spot on, and you’ll still have four bullets left in case you run into any more.

D: Whoa, calm down there – that’s too many reloads. Don’t get so trigger happy, you can’t afford to waste your precious ammunition.

How to work it out: You’re going to have to fire 50 shots to kill 50 zombies (we’ll cover the subject of what happens if you aren’t a perfect shot in a later problem). You’ve got six bullets in your gun already, so that’s 6 zombies dead before you have to reload meaning there’s 44 left (50 – 6). Each time you reload the gun, you put six bullets into it, so it we divided 44 (the number of bullets needed to kill the rest of the undead horde) by 6 (the number of bullets the gun can hold), we get 7.333. Since you can’t load a gun 0.333 times, this number needs to be rounded up to 8, and so we arrive at the answer. If there had been 48 zombies, the answer would be (48 – 6)/6, which is 7 (there’s no decimal fraction so there’s no need to round the answer up). If there were 52 zombies, the answer would be (52 – 6)/6, which is 7.6667, so again you’d need to reload your gun 8 times but this time you’d only have two bullets left in the gun by the time they’re all dead.

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 Responses to “1. The Reload Problem”

  1. Jack Flacco 22/04/2013 at 19:21 #

    Now why can’t all math problems be this enjoyable? Did I say enjoyable? I meant entertaining. A math student should not have any trouble when encountering questions like these! I have to hand it to you, Colin…this was very creative. Keep up the great work! 🙂

    • cmdrysdale 22/04/2013 at 19:31 #

      Hi Jack,

      Thanks for the feedback. It’s nice to know others out there appreciate this. The aim is to get a total of 50 such problems together and them publish them in a book called ‘The Little Book Of Zombie Mathematics: 50 zombie-based maths problems’. I’ve got about 30 roughed out so far and this blog gives me a reason to work on them on a regular basis. Not too sure exactly who the audience for such a book would be but even if I can get one person to see that maths can be interesting and relevant (something I always struggled with at school even though I was good at it) then it will have achieved something!

      All the best,


  2. Eric 12/10/2015 at 19:59 #

    My students thought that talking about guns was inappropriate for school. I wasn’t sure how to handle that one, so I simply told them that we were talking about guns in relation to zombies. Our school library has a book on guns, so I don’t know that is any different. Thoughts?

    • Colin M. Drysdale 13/10/2015 at 00:13 #

      Hi Eric,

      This is a really tricky issue and one that I’ve had a discussion with a few teachers over. From my own perspective, coming from Scotland, where we banned handguns completely after one of the few school mass shooting incidents we have ever had, I can see how some should feel that we should never discuss guns in the classroom. However, I was also brought up in family environment where guns were part of family members jobs (as gillies and gamekeepers), so I was taught from a young age that guns, if used respectfully were simply tools. I think the issue to introduce here is that guns, in the right circumstance, are valuable (i.e. in truly defensive situations where you have no other choice – as would be the case with zombies), but in most normal situations, guns are an extreme response that is likely to cause more problems than it solves. Personally, I feel that guns are only a solution to things like zombies which, by their very definition, cannot be solved any other way, and since zombies don’t really exist, there are few real world situations where guns are the only solution. In this respect, maybe the best take-home point from this blog is that in anything short of a zombie apocalypse, you should always seek another solution than guns, and maybe this is the best learning point here – guns are only justified if you have tried and failed with all other solutions. But then again, I am just one person with an opinion based on my own personal experiences, and these make me both feel that guns should not be freely available, but that those who have access to them should be taught the very strict conditions under which it is acceptable to use guns (i.e. very few situations less than the dead rising from the grave to consume the living).

      Sorry not to be able to be more enlightening here, but maybe this is one of those cases where you can use the discussion to think about how different communities or groups of people view gun use and ownership. In this context, it is worth considering various situations in various countries. In Britain, after the Dunblane massacre, handguns were banned completely despite the gun lobby. In South Africa, to shoot through a closed door of a bathroom and kill someone is manslaughter rather than murder. In Switzerland, they have a standing army consisting of the majority of the population, but very few, if any mass killings. Guns are prevalent in countries like Canada, but we rarely see mass shootings there. In the US, gun ownership is defended as a right, but it results in many people being killed (and mass shootings are only the tip of the iceberg on this front). If zombies were to exist, then it would be really useful to have easy access to guns, but if they don’t, does such easy access to guns cause many more unneeded deaths?

      I hope this helps, and I’d be interested to hear our thoughts, or anyone elses on this subject.

      All the best,


      I don’t claim to know the answers here, but maybe zombies are potentially interesting starting points for discussions on the roles of guns in the wider society.

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