Question

a box contains 12 balls of which summer red in colour if 6 more red balls are put in the ball 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 ball in the back

Answer 1

Let the no. of red ball be x.
P(E) = No. of outcomes favourable to E / Total no. of possible outcomes
P(red ball) = x/12 ....(1)

Now after adding 6 more red balls, the no. of red balls in bag bcomes x + 6.
After ading Probability bcomes, P(red ball) = (x+6)/12 ....(2)

As per given, (x+6)/12 = 2 (x/12)
(x+6)/12 = x/6
(x+6)/2 = x
x+6 = 2x
2x - x = 6
x = 6
Therefore the no. of red balls was 6 before adding and became 12 after adding!

Hope it Helped!!

Answer 2

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