Question

A box of colored crayons contains 11 distinct colors. In how many ways can 2 colors be chosen, assuming that the order of the colors chosen doesn’t matter? (If necessary consult a list of formulas.)

Answer 1

55

Explanation:

Equation is a = n * (n-1)

11 * 10 = 110

Order doesn't matter, and two colors, so divide by 2.

110/2 = 55

Answer 2

55

Explanation:

The first crayon is chosen out of 11,so there are 11 choices

11

The second crayon is chosen out of 10 crayons left so there are 10 choices

10

11*10 = 110

But we do not care about the order, so we divide by 2 since there are 2 places

110/2 =55