Short Answer TypeNumber of red balls in the bag = 5
Let number of blue balls in the bag = x
Now, total number of balls in the bag = x + 5
i.e., n( S) = n + 5
(i) Let ‘A’ be the favourable outcomes of getting blue balls, then
n( A) = x
Therefore,
P(A) = 
(i) Let 'B' be the favourable outcomes of getting red balls, then
n(B) = 5
Therefore,
P(B) = 
According to question :
P(A) = 4 P (B)
Hencem the number of blue balls in the bag is 20.
A box contains 5 red balls, 4 green balls and 7 white balls. A ball is drawn at random from the box. Find the probability that the ball drawn is
(a) White (b) neither red nor white
(i) white ball or a green ball.
(ii) neither a green ball not a red ball.
Cards marked with the numbers 2 to 101 are placed in a box and mixed throughly. One card is drawn from this box. Find the probability that the number on the cards is
(i) an even number
(ii) a number less than 14.
(iii) a number which is a perfect square.
(iv) a prime n umber less than 20.
18 Cards, numbered 1, 2, 3, ..., 18 are put in a box and mixed throughly. A card is drawn at random from the box. Find the probability that the Card drawn bears
(i) an even number
(ii) a number divisible by 2 or 3
12 cards, numbered 1, 2,3......., 12 are put in a box and mixed throughly. A card is drawn at random from the box. Find the probability that the card drawn bears
(i) an even number
(ii) a number divisible by 2 or 3.
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