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 is now double of what it was before. Find x


Total number of balls = 12

Total number of black balls = x


P (getting a black ball) =


If 6 more black balls are put in the box, then


Total number of balls = 12 + 6 = 18


Total number of black balls = x + 6


P (getting a black ball now) =


According to the given condition,


2 () =


3x = x + 6


2x = 6


x = 3


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