There are seven shuffled question cards left in a game. Kim has to pick two of them and answer them both correctly to win. What is the greatest number of different pairs of question cards she can pick?

Question

Mathematics

Abraham Kent

5 December, 02:51

There are seven shuffled question cards left in a game. Kim has to pick two of them and answer them both correctly to win. What is the greatest number of different pairs of question cards she can pick?

+3

Answers (1)

Know the Answer?

Leland Friedman · Answer 1

The order does not matter so you use the "n choose k" formula ...

n! / (k! (n-k) !) where n=number of cards and k equal the number you are going to choose ... so:

7! (2! (7-2) !)

7! / (2!5!)

21