Below is the marginal distribution for X

X	0	10	20
Probability	0.3	0.34	0.36

Below is the marginal distribution for Y

Y	0	1	2	3
Probability	0.15	0.3	0.2	0.35

Below is the joint PMF table for X and Y

			Y
		0	1	2	3
	0	?	0.05	0.1	0.1
X	10	0.02	0.15	?	?
	20	?	0.1	0.08	0.1

Fill in the rest of the joint PMF and compute the covariance between X and Y.