. A bag contains 5 red balls and some blue balls

Best Answer

Explanation:-

Probability = Number of possible outcomes/Total number of outcomes

As it is given in the question that the probability of drawing a blue ball is double that of a red ball, that means

2 × probability of drawing red ball = probability of drawing the blue ball.

Now, Number of red balls = 5

Let the number of blue balls be x

Total number of balls = x + 5

Probability of drawing red ball = Number of possible outcomes/Total number of outcomes

=5/(x+5)

Probability of drawing blue ball = Number of possible outcomes/Total number of outcomes

=5/(x+5)

Since the probability of drawing a blue ball is double that of a red ball 

x/x+5=2[5/x+5]

x=10

Final answer:-

Hence the number of blue balls = 10