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 blacks balls are added in the bag, the probability
of getting a black ball will be double. Find x.​

Answer 1

Answer:

getting a black ball = x / 12

x = 3

Step-by-step explanation:

initially number of balls = 12

when 6 black balls added = 18

initially number of black balls = x

when 6 black balls added = x+6

initially probability of black balls = x/12

now probability is double ie 2* x/12 = 2x/12

this is equal to probability of getting black ball after adding 6 black balls ie x+6/18

so x+6/18 = 2x/12

36x = 12x + 72

24x = 72

x = 3