Question

A bag contains 12 blue marbles and 8 red marbles. If shayne removes one red and does not replace it, then removes a second marble, what is the probabilty that both marbles will be red. A. 14/95, B. 7/50, C.4/25, D. 1/4

Answer 1

1/4

Explanation:

P{ both red} = favorable outcome / total outcome

= 2/8

=1/4

Answer 2

A. 14/95 This question is very poorly worded. If you take it as worded, the correct answer is 7/19 because the first condition "Shayne has removed a red marble" is already satisfied. But since it's not an available choice, I will assume the question actually is "If Shayne selected two marbles without replacing the first, what's the probability that both marbles are red?" And for that question we have 1st marble being red There's 8 out 20 red marbles, so the probability of selecting a red marble is 8/20. 2nd marble being red Now there's 7 out of 19 marbles being red. So the probability of the 2nd marble being red is 7/19. And the combined probability of both marbles being red is 8/20 * 7/19 = 56/380 = 14/95 So the answer is A. 14/95