Question

10. A bag contains 4 red balls, 6 green balls and some white balls. If the probability of not drawing a white ball in one draw be \(\frac{2}{3}\) then find the number of white balls.

Answer 1

No of white balls = 5

Explanation:

Given that,

Total no of red balls = 4

Total no of green balls = 6

The probability of not drawing a white ball in one draw be,
`P=(2)/(3)`

We need to find the number of white balls. Let there are x balls.

The probability of drawing a white ball = 1 - the probability of not drawing a white ball

= 1 -2/3

= 1/3

Using the formula for solving probability of having a white ball.

`P=\frac{\text{favorable outcome}}{\text{total no of outcomes}}\\\\(1)/(3)=(x)/(4+6+x)\\\\(1)/(3)=(x)/(10+x)\\\\10+x=3x\\\\10=2x\\\\x=5`

Hence, there are 5 white balls.