87 Suppose that the useful life of a particular car battery measured in months decays with parameter 0 025 We are interested in the life of the battery a Define the random variable X b Is X continuous or discrete C X d On average how long would you expect one car battery tollast e On average how long would you expect nine car batteries to last if they are used one after another f Find the probability that a car battery lasts more than 36 months 9 Seventy percent of the batteries last at least how long