2) Let $f_{xy}(x,y)$ be a joint density for the ordered pair (X,Y) in which X and Y are **continuous** random variables.
$$f_{xy}(x,y)=\frac{1}{3}(x+y)$$
$$0\leq x\leq 1$$
$$0\leq y\leq 2$$
a) Find the probability that X is less than 0.5 and Y is greater than 1.
b) Find the probability that X is greater 0.75.
c) Find the marginal density function on X, denoted by $f_x(x)$
d) Calculate E[X]