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 rd ball doubles than what it was before . then what is the probability of getting a red ball

Answer 1

Answer:

1/4

Step-by-step explanation:

Let the initial number of red balls be x

The probability of getting a red ball will be :

x/12

When 6 red balls are added the total number of balls become :

12 + 6 = 18

The probability of getting a red ball becomes :

(x + 6)/18

From the question :

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

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

18(2x) = 12(x + 6)

36x = 12x + 72

36x - 12x = 72

24x = 72

x = 3

The probability of getting a red ball is thus :

3/12 = 1/4

Answer 2

Answer:

1/4

Step-by-step explanation:

Let the initial number of red balls be x

The probability of getting a red ball will be :

x/12

When 6 red balls are added the total number of balls become :

12 + 6 = 18

The probability of getting a red ball becomes :

(x + 6)/18

From the question :

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

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

18(2x) = 12(x + 6)

36x = 12x + 72

36x - 12x = 72

24x = 72

x = 3

The probability of getting a red ball is thus :

3/12 = 1/4