A player is playing a game with a black box in which there are 2 red balls and 4 white balls. The player is asked to pick two balls at the same time. If he picks 2 red balls, he will win 10 dollars, if he picks 1 red ball and 1 white ball, he will win 4 dollars, otherwise, he will lose 2 dollars (or, win -2 dollars).

a)Let be the money he wins when playing a game. Give the probability distribution of x.

b) Calculate the expectation and variance of x.