A box contains 12 red balls and an unknown number of blue balls. If the probability of drawing a blue ball is 1 / 3, how many blue balls are there?
Q1. A box contains 12 red balls and an unknown number of blue balls. If the probability of drawing a blue ball is 1 / 3, how many blue balls are there?
Answer: 6
Explanation: Let's denote the number of blue balls as x. The total number of balls is 12 + x. The probability of drawing a blue ball is x / (12 + x) = 1 / 3. Solving this, 3x = 12 + x, so 2x = 12, and x = 6.