Question

a bag contains 3 green balls and some white balls. if the probability of drawing a white ball is thrice
that of a green ball. find the number of white balls in bag

Answer 1

No. of green balls = 3
No. of white balls = x
If probability to get a white ball is thrice that of 3 , then x = 3×3 = 9

Answer 2

Answer:

Number of white balls are 9 balls

Step-by-step explanation:

Given that a bag contains 3 green balls and some white balls. if the probability of drawing a white ball is thrice  that of a green ball.

we have to find the number of white balls in bag

Let the number of white balls=x

Green balls=3

Total number of balls in a bag=3+x

$P(white\thinspace balls)=\frac{\text{No. of white balls}}{\text{Total number of balls}}=\frac{x}{3+x}$

$P(green\thinspace balls)=\frac{\text{No. of green balls}}{\text{Total number of balls}}=\frac{3}{3+x}$

As,probability of drawing a white ball is thrice  that of a green ball.

⇒  $\frac{x}{3+x}=3(\frac{3}{3+x})$

⇒ $x=9$

Number of white balls are 9 balls