Greenfield college has a large number of students. Each student goes to college by car, by bus or on foot, and their choice is independent of every other student. The probability that a student travels by car is 0.4. The probability that a student travels by bus is 0.35.
(a)[1]
3 students from Greenfield college are chosen at random. Find the probability that none of these 3 students travel to college by car.
(b)[3]
11 students from Greenfield college are chosen at random. Find the probability that fewer than 9 of these 11 students travel to college by car or by bus.
Worked solution & mark scheme
This 4-mark question has a full step-by-step worked solution and mark scheme. One marking point: “$[(0.6)^3] = 0.216 = \frac{27}{125}$” …