Can anyone help me with the following problem asap:

There are 9 tennis balls in a box, of which only 5 have not previously been used. Four of the balls are randomly chosen from the box. Let 'z' be the number of new balls among the selected ones:

(a) Find the probability Distribution of z

(b) Evaluate the expectation E(z)

(c) Evaluate the variance Var(z)

Cheers Guys!!!