A box in a certain supply room contains four green balls six

A box in a certain supply room contains four green balls, six red balls, six yellow balls,and four blue balls. Suppose that four balls are randomly selected.

(a) What is the probability that exactly three of the selected balls are red?

(b) What is the probability that all four of the selected balls have the same color?

(c) What is the probability that one ball of each type is selected?

(d) Suppose now that balls are to be selected one by one until a red ball is found. What is theprobability that it is necessary to examine at least eight balls?

Solution