Question -
Answer -
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
Solution:
Total number of black balls = x
Total number of balls = 12
P(E) = (Number of favourable outcomes/ Totalnumber of outcomes)
P (getting black balls) = x/12 ——————-(i)
Now, when 6 more black balls are added,
Total balls become = 18
∴ Total number of black balls = x+6
Now, P (getting black balls) = (x+6)/18——————-(ii)
It’s given that, the probability of drawing a black ball now is double of what it wasbefore
(ii) = 2 × (i)
(x+6)/18 = 2 × (x/12)
x + 6 = 3x
2x = 6
∴ x = 3