Quick Start Company makes 12-volt car batteries. After manyyears of product testing, the company knows that the average lifeof a Quick Start battery is normally distributed, with a mean of45.0 months and a standard deviation of 9.1 months.
(a) If Quick Start guarantees a full refund on any battery thatfails within the 36-month period after purchase, what percentage ofits batteries will the company expect to replace? (Round youranswer to two decimal places.)
_ %
(b) If Quick Start does not want to make refunds for more than 13%of its batteries under the full-refund guarantee policy, for howlong should the company guarantee the batteries (to the nearestmonth)?
_ months