X represents the number of red balls drawn.

∴ X can take values 0,1,2 or 3

∵ there are total 10 balls

n(S) = total possible ways of selecting 2 balls =

P(X = 0) = P(selecting no red balls) =

P(X = 1) = P(selecting 1 red ball and 2 black balls)

=

P(X = 2) = P(selecting 2 red balls and 1 black ball)

=

P(X = 3) = P(selecting 3 red balls and 0 black ball)

=

Now we have p_i and x_i.

Following table represents the probability distribution of X :