Question

A bag contains 12 balls out of which x are black balls.find the probability of getting a black ball if one ball is drawn.if 6 more black balls are added in the bag,the probability of getting a black ball will be double.Find x​

Answer 1

Total no of  balls =12

no of black balls = x       (case 1)

p(e) = x/12

no of black balls = 6+x       (case 2)

gn ; p(E) = 2 p(e)

6+x/12 = 2*x/12

6+x = 2x

6-x= 0

x =6 Ans..