Let X1 and X2 be two independent random variables that are uniformly distributed on the interval [0; 1], i.e. X1 Uni[0; 1] and X2 Uni[0; 1]. 1. Find the expectation E(|X1-X2|), where |X1-X2| stands for the absolute value of the random variables |X1 - X2|. 2. Find the expectation E(max(X1; X2)), where max(a; b) is the maximum of a and b. 3. Find the variance Var(|X1 - X2|).