Question

A bag contains 5 red balls and some blue balls. If the probability of drawing a blue ballfrom the bag is thrice that of the red ball, find the number of blue balls in the bag.

Answer 1

let x is blue balls
according to question
probability of blue balls=3(probability of red balls)
5/x+5 ×(3)=x/x+5
15/x+5=x/x+5
15 =x

Answer 2

Answer:

Number of red balls are 15 balls

Step-by-step explanation:

Given a bag contains 5 red balls and some blue balls. If the probability of drawing a blue ball from the bag is thrice that of the red ball,

we have to find the number of blue balls in the bag.

Let the number of blue balls=x

Number of red balls =5 balls

Total balls=5+x

$P(\text{blue balls})=\frac{\text{Number of blue balls}}{\text{Total number of balls}}=\frac{x}{5+x}$

$P(\text{red balls})=\frac{\text{Number of red balls}}{\text{Total number of balls}}=\frac{5}{5+x}$

As probability of drawing a blue ball from the bag is thrice that of the red ball

$\frac{x}{5+x}=3(\frac{5}{5+x})$

$x=15$

Hence, number of red balls are 15 balls