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?
If6 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.

Answer 1

Answer:

x=3

Step-by-step explanation:

P(x)=x/12

when 6 more balls are in bag.

P(x+6)=x+6/12+6

P(x+6)=x+6/18

P(x+6)=2×P(x)

x+6/18=2×x/12

x+6/18=x/6

6(x+6)=18x

6x+36=18x

18x-6x=36

12x=36

x=36/12

x=3

Answer 2

Answer:

X = 3 (Black Balls)

Step-by-step explanation:

Total balls=12

Black balls= X

Probability of black ball = X/12

If 6 more black balls added then,

(X/12)×2 = 6+X/18

X/6 = 6+X/18

18X = 36 + 6X

12X = 36

X = 3