# When 3 marbles a picked from a box with 16 blue, 12 red and 18 green marbles, what is the probability that only the 3rd marble is blue.

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3 marbles are picked from a box that has 16 blue, 12 red and 18 green marbles.

The number of colors of each of the three marbles that can be picked is 3. There are 3^3 = 27 ways in which the marbles can be picked. If only the third marble has to be blue, the other two marbles can be red or green in 2^2 = 4 ways.

This gives the probability that only the 3rd marble is blue as 4/27.

**There is a probability of 4/27 that only the 3rd marble is blue.**