Question

1 A bag contains 5 red balls and some blue balls. If the probability of drawing a blue ball
is double that ofa red ball, determine the number of blue balls in the bag.​

Answer 1

Answer:

10 blue ball are there in the bag

Answer 2

Answer:

Given number of red balls = 5

Let the number of blue balls be x.

Total number of Balls =5+x.

According to the question,

Probability (getting blue balls) =2×Probability (getting red balls)

As we know,

$Probability = \frac{number \: of \: events}{total \: number \: of \: outcomes}$

Thus,

$Probability(getting \: blue \: ball) = \frac{x}{x + 5}$

$Probability(getting \: red \: balls) = \frac{5}{x + 5}$

Calculation :

$\frac{x}{x + 5} = 2 \times \frac{5}{x + 5}$

$\frac{x}{x + 5} = \frac{10}{x + 5}$

On cancelling the Denominators,we get

x = 10.

Therefore, there are 10 blue balls and 5 red balls in the bag.