Question

A bag contains 5 red balls and some blue balls. If the probability of drawing a blue ball is double that of a red ball. Determine the number of blue balls in the bag?

• A. 5
• B. 10
• C. 8
• D. 15

Answer 1

Answer:

B. 10

Number of red ball = 5 Number of blue ball = X Total = 5 + x P{getting red} = 5/(5 + X) P{getting blue} = X/(5+X) X/(5 + X) = 2 × 5/(5 + X) On solving X = 10 Number of blue balls in the bag = 10