Hello tutors, can I please get you assistance with the following ? Thank You so much

Consider the planning of undergraduate education for all three kids that a young couple plans to have. The costs depend on the number of kids that go to college (X) and the number of years each takes to complete the degree (Y). We denote the cost by C. Thus

C=g(X,Y)

Suppose the joint probability mass function of X and Y for the planning couple is as follows