A box contains three blue balls and two red balls. Two balls are randomly drawn from the box one after another without replacement. Determine the probability that:

Question

a) two balls drawn are both red

b) one ball is red and one ball is blue

c) at least one of two drawn balls is blue.

Answer 1

a) 2/5 * 1/4 = 2/20 = 1/10

b) 2/5 * 3/4 = 6/20 = 3/10

c) 1 - (2/5*1/4) = 1 - 2/20 = 1 - 1/10 = 9/10