Questions tagged [calculation-puzzle]

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

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5
votes
2answers
542 views

Choosing units for drug testing

Here's a third puzzle that I found in a book, slightly paraphrased because I don't entirely remember the format of the original. A medical researcher is trying to test the effect of a certain drug ...
5
votes
1answer
725 views

Shuffling Cards

I was just thinking about this. Let's say that we have a card deck with 54 cards and the $n$th card from the top is flipped. We repeat a short process of cutting the deck directly in the middle and ...
44
votes
3answers
11k views

I don't know the two numbers… but now I do

Two perfect logicians, Summer and Proctor, are told that integers $x$ and $y$ have been chosen such that $1 < x < y$ and $x+y < 100$. Summer is given the value $x+y$ and Proctor is given the ...
8
votes
4answers
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. ...
57
votes
10answers
42k 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 ...
13
votes
2answers
1k 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?
20
votes
1answer
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 ...
2
votes
2answers
468 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 ...
15
votes
2answers
17k 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 ...
0
votes
4answers
1k views

Three Gallon Jug and 5 Gallon Jug [duplicate]

One of the classical puzzles is pouring water into the 5 gallon jug so there is 4 gallons of water remaining. This was popularized by Bruce Willis in "Die Hard with a Vengeance". I was wondering ...
5
votes
4answers
1k views

Round-Robin Tournament

20 teams played in a round-robin tournament. The winner of each game got 1 point, and the loser got 0; there were no draws. Each team's total score was a square number. At least one team had a unique ...