Easy three questions need answer ASAP (30 mins)

Suppose that you have a loaded die,where the probability of landing on each number is given by the following:

x	1	2	3	4	5	6
P(X=x)	0.3	0.1	0.1	0.1	0.1	.3

1.)Find the expected value of a single roll of the die.

2.)Find the standard deviation of a single roll of the die.

3.)If the coefficient of correlationr= 0 .80, the standard deviations ofXandYare 2 and .5, respectively. Then Cov(X,Y) must be...