When we say that a set of random variables, X1, X2, ......... , X\X, Y are the duration (in years) of a hard drive for the CS department's ofce and the Stats Department's ofce, respectively. X, Y are independent and exponential with parameter A: 0.1 for CS and A = 0.083333 for the Stats department, respectively. The store selling these hard drives exaggerates a little, and says to the CS department that the life of the hard drive sold to CS will be twice as long as its true expected value. The store tells the Statistics Department that the hard drive sold to it will last 3 times longer than its true expected value. From the point of view of the store, what is the expected total life of the two hard drives together? 0 56 years 0 45 years 0 0.45 years 0 19 years. 1 5 Let X and Y be two random variables. What is the following expression equal to? E[( ax + by) - (alex + buy ) ]" O a'of + bor + 2abCou (X, Y) O Var(aX+by) O Cov(X,Y) OE ( X - MX) + ( Y + at My)? + (X-6) )