Question 1150040
number of ways to choose 5 is 210C5
find probability all are not defective is the complement of the answer.
that is 206C5

Also, the probability of the first not being defective is 206/210, the second 205/209. then 204/208, and 203/207.

That probability is 0.9075 of not being defective.

The question asks for probability of at least 1 being defective (so he doesn't have to pay), and that is the complement or 0.0925.