Suppose that only 25% of all drivers come to a complete stop at an intersection having flashing red lights in all directions when no other cars are visible.
a. What is the probability that, of 20 randomly chosen drivers coming to an intersection, at least 6 will come to a complete stop?
b. What is the probability that 5 cars need to come to the intersection to obtain the first complete stop.
c. What is the probability that at most 12 cars need to come to the intersection to obtain 5 complete stops. (Hint: 7 failures till the 5th success)