During an assembly process parts arrive just as they are nee

During an assembly process, parts arrive just as they are needed. However, at one station, the probability is 0.01 that a defective part will arrive in a one-hour period. Find the probability that Exactly 1 defective part arrives in a 4-hour span; 1 or more defective parts arrive in a 4-hour span; Exactly 1 defective part arrives in a 4-hour span and exactly I defective part arrives in the next 4-hour span.

Solution

(a) P = 4C1 * 0.01* (0.99)^3 = 0.0388 (b) Probability of one ore more = 1-(probability of no defect) = 1- (0.99)^4 = 0.0394 (c) P = 0.0388 * 0.0388 = 0.00150544