Question

1.A box contains 12 balls out of which X are black. if 1 balls drawn at random from the box , what is the probability that it will be black ball's ?
2. If 6 more black box are put in the box , the probability a black ball is now double of what is was before . Find X
10 mark ques​

Answer 1

Answer:

1) probability will be between 1 & 0 / equal to 1,0

2) x=9

Step-by-step explanation:

I don't know whether it is true or false.

i'm not able to explain it, sorry :(

Answer 2

Answer:

1. $\frac{x}{12}$

2. 6

Step-by-step explanation:

1.

Total no. outcomes = 12

Favourable outcomes = x

P (event) = $\frac{favourable..outcomes}{total..no..outcomes}$

P (drawing a black ball) = $\frac{x}{12}$

∴ the probability of drawing a black ball is $\frac{x}{12}$

2.

Total no. of outcomes = 12 + 6 = 18

Favourable outcomes = x + 6

P (event) = $\frac{favourable..outcomes}{total..no..outcomes}$

P (drawing a black ball) = $\frac{x+6}{12}$

Condition: If 6 more black balls are put in the box, the probability is now double of what it was before.

∴ $\frac{x+6}{12}$ = 2 × $\frac{x}{12}$

⇒ $\frac{x+6}{12}$ = $\frac{x}{6}$

⇒ 6 (x+6) = 12x

⇒ 6x + 36 = 12x

⇒ 12x = 6x + 36

⇒ 12x - 6x = 36

⇒ 6x = 36

⇒ x = $\frac{36}{6}$ = 6

∴ x = 6

∴ The value of x is 6

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