Question

a box contains 12 balls of which some are red in colour if 6 more red balls are put in the box and a ball is drawn at random the probability of drawing a red ball Doubles then what it was before find the number of red balls in the bag

Answer 1

Answer:

Step-by-step explanation:

Let the no. of red balls be= x

The total no. of balls= 12

Probability of a red ball= x/12

Now,

No. of red balls added= 6–> x+ 6

The probability now is x+6/ 18

X+ 6/ 18= 2X/ 12

On cross multiplication,

12x + 72= 36x

X= 3

Thus no. of red balls in the bag previously was 3 and now is 9.

Hope it helps:)

Answer 2

Answer:

Step-by-step explanation: total balls=12

Let red balls be x

P= x/12

Now red balls =x+6

So P=(x+6)/12

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

X+6=2x

X=6