Question

A bag contains 4 green marbles, 3 red marbles, and 7

blue marbles. One marble is taken from the bag and put

back after checking its color. A second marble is then

taken out. What is the probability that the first is blue

and the second red?

Answer 1

3/28

Explanation:

There are 14 marbles in the bag. So, the probability of choosing a blue marble is 7/14 or 1/2. Since the first marble is replaced, the bag still has 14 marbles in it. Then the probability of choosing a red marble is 3/14. The probability of choosing the blue, then the red is 1/2 x 3/14 = 3/28