A box contains 5 red bowls, 6 yellow bowls and 3 white bowls. If 4 bowls are randomly drawn from the box at the same time,

Question

(a)find the probability that exactly 2 red bowls are drawn;
(b)find the probability that at least 2 red bowls are drawn.

My work:
(a) (5/14)^2(6/14)(3/14)+(5/14)^2(6/14)^2+(5/14)^2(3/14)^2=225/19208
(b) 225/19208+(5/14)^3(6/14)+(5/14)^3(3/14)+(5/14)^4=275/4802