Question

A bag contains 12 balls out of which x white.1)If one ball is drawn at random, what is the probabilitythat it will be a white ball?ii) If 6 more white balls are put in the bag, the probability of drawing a white ball will be double than that in i). Find x.

Answer 1

1)
no of balls=12
no of white balls =x
p(white ball) = no. of favourable outcomes/no of total possible outcomes

= x/12----(1)
2)
if 6 more white balls are put in the bag
no of total balls = 18
no of white balls =x+6
p(white balls)= (x+6)/18---(2)

therefore
(x+6)/18 = 2*x/12
(x+6)/18 =x/6
x+6 = 18x/6
x+6=3x
6=3x-x
6=2x
2x=6
x=6/2
x=3

Answer 2

this is the answer......