You own 7 pairs of jeans and want to take 2 of them with you on vacation. In how many ways can you choose 2 pairs of jeans
There are 21 ways to choose 2 pairs of jeans from 7 pairs.
This is because the formula for calculating the number of combinations of k items from a set of n items (without repetition) is:
n! / (k! * (n-k)!)
In this case, n = 7 and k = 2, so the calculation is:
7! / (2! * (7-2)!)
= (7 * 6 * 5 * 4 * 3 * 2 * 1) / ((2 * 1) * (5 * 4 * 3 * 2 * 1))
= 21.