Some question: There are 18 balls in a jar. You take out 3 black balls without putting them back inside, and now the probability of pulling out a black ball is 1/3. How many blue balls were there in the beginning?\nOptions:\n(A) 12.\n(B) 9.\n(C) 8.\n(D) 7.\n(E) 6.
Some stream of consciousness:
User
8 = 3 blue balls + 15 / 3 The answer: (C).
Assistant