probability statistics

Question

Suppose a jar contains 13 red marbles and 36 blue marbles. If 2 marbles are randomly chosen from the jar at the same time, find the probability that both marbles are red. Round your answer to four decimal places.

Answer 1

49 total marbles 13 red

Event A = getting red on first draw

Event B = getting red on 2nd draw

P(A) = 13/49

P(B given A) = P(B|A) = 12/48 (since one less red marble and one less marble overall)

P(A and B) = P(A) * P(B|A) = 13/49 * 12/48 = 0.0663