A local car wash specializes in quick car washes. When a car arrives, there is a promised completion time. We assume that cars arrive independent of each other as are times to complete the wash. We assume also that the probability of a car being late (not being finished by the promised completion time) is the same for each car. Based on observations of the process we know that P(car is late) = 0.20

Determine the probability that exactly 4 of the next 15 cars washed are late.