An aircraft seam requires 25 rivets. The seam will have to reworked if any of these rivets is defective. Suppose rivets are defective independently of one another, each with the same probablility.
a. If 20% of all seams need reqorking, what is the probability that rivets is defective?
b. How small should the probability of a defective be to ensure that only 10% of all seams need reworking?