2. A new apartment complex consists of 10 apartments, each rented for one year. There is a 15 percent chance that any one apartment rented for a year will be vacated before the end of the year.

a. What is the expected number of apartments that will be become vacant before the end of the year? What is the variance?

b. What is the probability that more than 1 apartments will be vacated before the end of the year?

c. What is the probability that at most 1 apartment will be vacated before the end of the year?

d. What is the probability that no apartment will be vacated before the end of the year given at most 1 apartment will be vacated before the end of the year?