Bunuel wrote:

A jar contains g green marbles and r red marbles. If 2 green and 14 red marbles are added, which of the following expresses the probability of then selecting a green marble at random?

A. g/r

B. (g+2)/(r+14)

C. (g+2)/(r+16)

D. (g+2)/(r+g+14)

E. (g+2)/(r+g+16)

Since the jar contains g green marbles and r red marbles, it contains a total of g + r marbles. Once 2 green and 14 red marbles are added, the jar then contains a total of g + r + 16 marbles, of which g + 2 are green marbles.

Thus, the probability of selecting a green marble is (g + 2)/(g + r + 16).

Answer: E

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