Question

a box contains 12 balls out of which X are black if one ball is drawn at random from the box what is the probability that it will be a black ball if 6 more black balls are put in the box the probability of drawing a black ball now is double of what it was before find x​

Answer 1

Step-by-step explanation:

first case

p(black) = x/12

second case

p(black) = (x+6)/18

according to question

(x+6)/18 = 2*x/12

by cross multiplication

12*(x+6)=18*2*x

12x + 72 = 36x

72 = 36x-12x

72 = 24x

x=3

so the value of x is 3

hope u got it।।।।

Answer 2

Step-by-step explanation:

P(B)=X/12

now on adding 6 more black balls.

P(B)=(X+6)/18

thus acc to qs

(X+6)/18=2*(X/12)

implies that X=3