. (12 pts.) Let XUXI, and X3 represent the times necessary to perform three successive repair tasks at a certain service facility. Suppose they are independent normal random variables with expected values #1412, and #3 andvariances aoj, and of, respectively. Suppose ,ul 2 60, #2 = 64,.\"3 =80 and CJ'l =02 =03 =5. :1. Calculate P(X| + X2 +X3 S 210). b. What is E (X) , the expectation of A7 = x1+x2+x3? What is 0,7 , the standard 3 deviation of X? 0. Calculate PL? > 65) and P(62