let and be independent random variables representing the lifetime (in one billion years) of type a and type b stars, respectively. both variables have exponential distributions, and the mean of is 3 and the mean of is 11. what is the expected total lifetime of three type a stars and one type b star?

expectedtotal lifetime of three type a stars and one type b star is 20.exponential distributionfrequently addresses the elapsed time before a particular event. Consider the exponential distribution of the time (starting right now) before an earthquake happens. It is a continuous distribution that is frequently used to calculatetimewhen an event is anticipated to take place.independentrandom variables representing the lifetime (in one billion years) of type a and type b stars, respectively. both variables have exponential distributions, and the mean of is 3 and the mean of is 11.exponential distributionvisit