Study the following information carefully and answer the given questions.
There were some red, some green and some white balls in a bag. Probability of drawing 1 white ball from the bag is . `(1)/(3)` If there were 6 more red balls in the bag, the probability of getting 1 green ball would have been `(1)/(30)` less.
If sum of red, green and white balls is 30, then what is the probability of drawing 2 white ballsfrom the bag?

Options

A. `3//29`
B. `5//58`
C. `9//58`
D. `10//87`

Answer

A

Explanation

Let the number of white balls = w, the number of green balls = g and the number of red balls = r, then
`(w)/((w + g + r)) = (1)/(3)`
`rArr (w)/(30) = (1)/(3)`
`rArr w = 10`
Hence, the required probability ` = (10_(C_(2)))/(30_(C_(2))) = (10 xx 9)/( 30 xx 29) = (3)/(29)`