Please help I'm confused

Question

In a sample of 21 hand-held calculators, 12 are known to be nonfunctional. If 8 of these calculators are selected at random, what is the probability that exactly 6 in the selection are functional?

Answer 1

₈C₆ x (9/21)⁶ x (12/21)² = 0.05665

 

I don't know if I'm just overthinking that this is a binomial distribution but I really think it is.