The ratio of the number of red balls to blue balls in a bag is 3:5. If 6 red balls are added and 3 blue balls are removed, the new ratio of red balls to blue balls becomes 2:3. How many blue balls were initially in the bag?

✓ Correct Answer: Option C

Let initial red balls be 3x and blue balls be 5x. After changes, (3x+6)/(5x-3) = 2/3. Cross-multiply to get 3(3x+6) = 2(5x-3) => 9x+18 = 10x-6 => x = 24. Initial blue balls = 5x = 5(24) = 120. Wait, there is a calculation error. 9x+18 = 10x-6 => 18+6 = 10x-9x => x = 24. Initial blue balls = 5x = 5*24 = 120. This value is not in the options. Let me re-evaluate the question or my calculation.