A bag contains 7 red marbles, 12 white marbles, and 9 pink marbles. Find P (red or pink)

Question

9/112
7/12
5/8
4/7

Answer 1

P (red or pink) = P(red) + P(pink) - P(red and pink)

P(red) = 7/28
P(pink) = 9/28
P(red and pink) = 0 (red and pink marbles are mutually exclusive)

P(red or pink) = 7/28 + 9/28 = 16/28 = 4/7

Therefore, P(red or pink) = 4/7