Let X ~ exp(?)
MGF of X = ?/(1-t)
a) What is MGF of Y = 3X
b) Y has a common distribution, what is the pdf of Y?
c) Let X1,X2,....Xk be independent and identically distributedwith Xi ~ exp(?) and S = ? Xi (with i = 1 belowthe summation symbol, and k is on top of the summation symbol).What is the MGF of S?
d) S has a common distribution. What is the pdf of S?
