Quick Start Company makes 12-volt car batteries. From historical data,

Quick Start Company makes 12-volt car batteries. From historical data, the company knows that the life of such a battery is a normally distributed random variable with a mean life of 45months and a standard deviation of 10months.(a) What percentage of Quick Start 12-volt batteries will last between 32 months and 54 months ?(b) Seventy-five 12-volt batteries are randomly selectedn=75. What is the probability that the mean lifetime of the batteries in this sample will be between 43 and 44 months ?