Question

A ball is picked up at random from bag containing 12 balls out of which x are white. What is probablity that picked up is white? If 6 more white balls are put in the bag and a ball is picked up,the probability of picking up a white ball become twice the previous one find x.

Answer 1

Answer:

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