The weekly sales of Volvo's Cross Country station wagons are normally distributed witha mean of 1,000 and standard deviation of 250. Answer the following questions:
a. What is the probability that from 400 through 1,100 station wagons are sold during one week?
b. What is the probability that station wagons' sale is more than 1,100 for exactly 6 weeks out of the next 10 weeks?
c. There is a 1 percent chance that fewer than what number of station wagons is sold during a week?