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.
There are 12 balls in the box.
Therefore, total number of outcomes = 12
The number of favourable outcomes = x
Therefore, P (getting a black ball)
If 6 more balls put in the box, then,
Total number of outcomes = 12 + 6 = 18
And the number of favourable outcomes = x + 6
So, P (getting a black ball)
According to question,