An ice cream stand has 5 different flavours. A group of children come to the stand and each buys...

Question

... a double scoop cone with 2 flavours. Each of the children chooses a different combination of flavours and every combination is chosen. How many children are there?

Answer

There are 10 children.
(I would give you the process of how I got there, except I literally just sketched all the possible combinations, so that's not very helpful to you.

Answer

Basic combinatorics or statistics or whatever they call it.

You're choosing all combinations of 2 items from a list of 5 items without repetition.
=> Solution's the binomial coefficient.

(5 over 2) = 5! / (2! * (5-2)!) = 5 * 4 / (2 * 1) = 10.

An ice cream stand has 5 different flavours. A group of children come to the stand and each buys...

Answers (2)