1. A lady makes an attempt to hit the target. The probability of hitting the target is 3/8. What is the probability that the lady hits the target exactly 2 or 3 times in 5 attempts?

2. Suppose there is a disease, whose average incidence is 1 per million people. What is the probability that a city of 1 million people has at most twice the average incidence?

3. The mean number of customers arriving at a bank during a 15-minute period is 10. Find the probability that no customers will arrive at the bank during a 15-minute period.