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Class 10
Mathematics
Probability
a box contains 12 balls out of which x are black...

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?
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.

Answer:

Total no of balls = 12

Let the no. of black balls = x

P(E) of getting a black ball = [ x / 12]

(ii) When 6 more black balls added to bag

Total no of balls = 12 + 6 = 18

No of black balls = x + 6

P (black ball) = [(x + 6) / 18]

Acc. to question,

Before After

2 P(E)_B = P(E)_B

2 [x / 12] = [(x + 6) / 18]

x/6 = x + 6/18

x + 6 = 3x

2x = 6 => x =3

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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?
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.

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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? 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.

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Popular questions of class 10 Mathematics

Recently Viewed Questions of Class 10 Mathematics

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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?
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.