5.20 Costs of equipment maintenance are an important part of a firm’s budget. Each visit by a field representative to check out a malfunction in a word processing system costs $40. The word processing system is expected to malfunction approximately five times per month, and the standard deviation of the number of malfunctions is 2.

a Find the expected value and standard deviation of the monthly cost of visits by the field representative.

b How much should the firm budget per month to ensure that the cost of these visits will be covered at least 75% of the time?