A bag contains some red balls, some blue balls and some white balls. Out of which the number of blue balls is twice the number of white balls, and the probability of drawing a red ball is 1/2. Find the probability of drawing a white ball.

OR

All queens, aces and kings are removed from a pack of 52 cards. The remaining cards are well-shuffled, and then a card is drawn from it. Find the probability that the card is

(i) A black card (ii) A red card

(iii) A red face card

Let the number of red balls be x. And the number of white balls be y.

Then, number of blue balls = 2y

Now,

Total number of balls = (x + y + 2y) = (x + 3y)

Probability of drawing a red ball

Therefore,

2x = x + 3y

x = 3y….(1)

Now, total balls = x + x = 2x

Number of white balls = y

And from equation 1,

The probability of drawing a white ball

P(white ball)

Hence, the probability of drawing a white ball is .

OR

There is a total of 52 cards in a pack of cards.

Now, all queens, aces and kings are removed.

Therefore, total cards left = 52 – 12 = 40

In which,

Number of red cards = 20

Number of black cards = 20

(i) P(black card)

(ii) P(red card)

(iii) In face cards, only jacks are left. And out of them there are two red jack cards.

Therefore,