A bag contains 4 white balls and some red balls. If the probability of drawing a white ball from the bag is `2/5,` find the number of red balls in the bag.

A bag contains 5 red balls and some blue balls. If the probability of drawing a blue ball is double that of a red ball, find the number of blue balls in the bag.

A bag contains 5 red balls and some blue balls. If the probability of drawing a blue ball is double that of a red ball, find the number of blue balls in the bag.

A bag contains 15 white balls and some black balls. If the probability of drawing a black ball is thrice that of a white ball, find the number of black balls in the bag.

A bag contains 6 red balls and some blue balls. If the probability of drawing a blue ball from the bag is twice that of a red ball, find the number of blue balls in the bag.

A bag contains 5 red balls and some blue balls. If the probability of drawing a blue ball is double that of a red ball, determine the number of blue balls in the bag.

A bag contains 5 red balls and some blue balls. If the probability of drawing a blue ball is double that of a red ball, determine the number of blue balls in the bag.

A bag contains 7 white, 5 black and 4 red balls, find the probability that the balls is white.

A bag constains white, black and red ball only. A ball is draw at random form the bage. If the probability of getting a white balls is (3)/(10) and that of a black ball is (2)/(5) then find the probability of getting a red ball. If the bag contains 20 black balls, find the total number of balls in the bag.

A bag contains 5 white balls, 6 red balls and 9 green balls. A ball is drawn at random from the bag. Find the probability that the ball drawn is : (iii) neither a green ball nor a white ball.

There are 5 red and 4 black balls in a bag. The probability of drawing a red ball is: