An urn contains five green balls and eight white balls. a sample of four balls is selected at random from the urn.
(a) find the probability that the four balls have the same color.
(b) find the probability that the sample contains more green balls than white balls.
(a) the probability that the four balls have the same color is nothing.
(b) the probability that the sample contains more green balls than white balls is nothing.
(type an integer or a simplified fraction.