Question

An artist is trying to choose 5 covers for children’s books. There are 10 different covers to choose from. How many ways can the artist choose covers? (It’s a permutation and combination kind of problem)

Answer 1

252

Explanation:

The order of the books isn't important, so we'll use combinations.

The number of ways to choose 5 books from 10 is:

₁₀C₅ = 10! / (5! (10 − 5)!)

₁₀C₅ = 10! / (5! 5!)

₁₀C₅ = 10×9×8×7×6 / (5×4×3×2×1)

₁₀C₅ = 252