Question

A bag contains 18 balls out of which x balls are red.
(1)If one ball is drawn at random from the bag,what is the probablity that it is not red?
(2)If 2 more red balls are put in the bag,the probablity of drawing a
red ball will be 9/8 times the probablity of drawing a red ball in the first case.Find the value of x.​

Answer 1

Total number of balls = 18

Number of red balls = x

(1) p(red ball)=x/18

(2) 2 more red balls are put in the bag.

Now,the total number of balls 18+2=20

Now,p(red ball)=x+2/20

According to question

x+2/20=9/8×x/8

x+2/20=x/18

x+2/20=x/16

16x+32=20x

4x=32

x=8

hope it helps you