A lot of 20 batterries contains 6 that are defective If 5 ba

A lot of 20 batterries, contains 6 that are defective. If 5 batteries are sampled from this lot at random, calculate the probability that among the 5 batteries tested, exactly 2 will be defective.

Please explain all work, I\'m a bit confused at the question. Thanks!

Solution

There are 20C5 ways to choose any 5 batteries.

There are 14C3 ways to choose nondefectives, and 6C2 ways to choose defectives to satisfy the problem.

Thus, the probability is

P = [(14C3)(6C2)]/(20C5)

P = 0.352167183 [ANSWER]