65. Most four, year automobile leases allow up to 60,000 miles. If the lessee goes beyond this amount, a penalty of 20 cents per mile is added to the lease cost. Suppose the distribution of miles driven on four- year leases follows the normal distribution. The mean is 52,000 miles and the standard deviation is 5,000 miles. a. What percent of the leases will yield a penalty because of excess mileage? I}. If the automobile company wanted to change the terms of the lease so that 25 percent of the leases went over the limit, where should the new upper limit be set? c. One denition of a lowL mileage car is one that is 4 years old and has been driven less than 45,000 miles. What percent of the cars returned are considered low, mileage? 67. The annual sales of romance novels follow the normal distribution. However, the mean and the standard deviation are unknown. Forty percent of the time sales are more than 470,000, and 10 percent of the time sales are more than 500,000. What are the mean and the standard deviation? 69. DeKarte Tele Marketing Inc. is considering purchasing a machine that randomly selects and automatically dials telephone numbers. DeKoIte Telee Marketing makes most of its calls during the evening, so calls to business phones are wasted. The manufacturer of the machine claims that its programming reduces the calling to business phones to 15 percent of all calls. To test this claim, the director of purchasing at DeKone programmed the machine to select a sample of 150 phone numbers. What is die likelihood that more than 30 of the phone numbers selected are those of businesses, assuming the manufacturer's claim is correct? 71. "Boot Time" (the time between the appearance of the Bios screen to the rst le that is loaded in Windows) on Eric Mouser's personal computer follows an exponential distribution with a mean of 27 seconds. What is the probability his "boot" will require: a. Less than 15 seconds? I}. More than 60 seconds? c . Between 30 and 45 seconds? (I. What is the point below which only 10 percent of the boots occur