Problem: A certain firm uses a large fleet of delivery vehicles. Their records over a long period of time (during which their fleet size utilization may be assumed to have remained suitably constant) show that the average number of vehicles per day is 3. Estimate the probability on a given day when
i. all their vehicles will be serviceable
ii. more than 2 vehicles will be unserviceable
iii. exactly 4 vehicles will be unserviceable