Using the notation found here: Hypergeometric distribution - Wikipedia, the free encyclopedia
Y ~ Hypergeometric(m = 5, N = 20, n = 4)
(a) Substitute the above values into the pmf given at the above link. Note that the support of Y (that is, the values that Y can have) is 0, 1, 2, 3, 4.
(b) The probability that the largest value in the selection is at most 15 will be Pr(Y = 0) (why?).
(b) Calculate .