The time required for an automotive center to complete an oilchange service on an automobile approximately follows a normal?distribution, with a mean of 17 minutes and a standard deviation of2.5 minutes. ?(a) The automotive center guarantees customers thatthe service will take no longer than 20 minutes. If it does take?longer, the customer will receive the service for? half-price. Whatpercent of customers receive the service for? half-price? ?(b) Ifthe automotive center does not want to give the discount to morethan 5?% of its? customers, how long should it make the guaranteedtime? limit?
