# Questions tagged [calculation-puzzle]

A puzzle that involves numerical calculations, such as multiplication and addition.

687 questions
Filter by
Sorted by
Tagged with
2k views

### A Sand Timer Challenge

Which (if any) of these intervals is it possible to measure given two sand timers (which change from question to question)? There are no minute marks, halfway points, etc. A. 7 minutes with 4- and 5-...
496 views

### Your age and my age [closed]

This is not a very difficult problem, but it seems that it hasn't been asked here. It's one of my favorites, so here we go: I am twice as old as you were when I was as old as you are. When you ...
506 views

### Magic back yards

My back yard forms a rectangular grid of squares except some of the squares are missing as they are covered by pipes or a small tree. The layout is as follows. A 'x' indicates a square that is free ...
43k views

### Candle timing measurement [duplicate]

You are given two candles of equal size, which can burn 1 hour each. You have to measure 90 minutes with these candles. (There is no scale or clock). You are also given a lighter.
387k views

1k views

### How do I solve the “Between Worlds” Android puzzle game?

I've been struggling for a while with the Between Worlds Android game, and have not yet solved it. I've only noticed a couple vague properties that hold in localized cases. To operate the puzzle, ...
330 views

### Is there a more specific name for this type of arithmetic puzzle?

There are arithmetic puzzles with some numbers (typically four) and rules for combining them (perhaps just the four basic arithmetic operators or including things like combining digits 2 and 3 to make ...
1k views

2k views

### Travellers across a desert

This is a problem I once found in a math textbook a tutor used with me. A group of explorers is trying to get from their base camp to another camp which is eight days' walk through the desert. ...
49k views

### A camel transporting bananas

A somewhat well-known puzzle is described as such: You have a pile of 3,000 bananas. You wish to transport them to a place 1,000 miles away on the back of a camel; however, the camel can only carry ...
2k views

### End of the world - on a Sunday?

If the end of the world was supposed to come on the first day of a new century, what would be the chances that it would happen on a Sunday?
2k views

### How do I tell the children's ages?

My friend once told me a logic puzzle along the lines of: A student asks a teacher what the ages of the teacher's three kids are. The teacher said, "the product of their ages is 72, and the sum of ...
469 views

### The problem of the hired hands' work rates [closed]

A farmer is looking to hire some hired hands. His usual three hires are named Barry, Harry, and Larry. He knows from hiring them before that: Working together, Barry and Harry can plow an acre in ...
19k views

### What's the fewest weights you need to balance any weight from 1 to 40 pounds?

Suppose you want to create a set of weights so that any object with an integer weight from 1 to 40 pounds can be balanced on a two-sided scale by placing a certain combination of these weights onto ...