# Probability math homework help

1. Jan 27, 2008

### tronter

An aircraft requires $$25$$ rivets. The seam will have to be reworked if any of these rivets is defective. Suppose rivets are defective independently of one another, each with same probability.

(a) If $$20 \%$$ of all seams need reworking, what is the probability that a rivet is defective?

So this is equaled to $$\frac{1}{25}$$?

(b) How small should the probability of a defective rivet be to ensure that only $$10 \%$$ of all seams need reworking?

2. Jan 28, 2008

### CompuChip

Have you learned about binomial distribution yet?

3. Jan 28, 2008

### tronter

figured it out, thanks.