Question

You have a bag of 15 marbles. 8 are red. 5 are blue. 2 are green. If you pull out two marbles without replacement, what is the probability that one, but not both, of them, will be blue?

a
33.3%
b
57.1%
c
66.6%
d
47.6%

Answer 1

a 33.3 percent

Explanation:

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Answer 2

• D. 47.6%

Explanation:

Given

• Total marbles = 15
• Blue marbles = 5

Solution

There are two possible scenarios

1. First marble is blue and second marble is not blue:

• P(blue) = 5/15 = 1/3
• P(not blue) = 10/14 = 5/7
• P(blue and not blue) = 1/3*5/7 = 5/21

2. First marble is not blue and second marble is blue:

• P(not blue and blue) = 10/15*5/14 = 2/3*5/14= 5/21

The probability that one, but not both, of them, will be blue:

• 5/21 + 5/21 = 10/21 = 0.476 = 47.6%

Correct option is D