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

A boy contains 15 white and some black balls. If the probability of drawing a black ball from the bag is thrice that of drawing a white ball, find the number of black 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 3 red,4 white and 7 black balls.The probability of drawing a red or a black ball is

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.

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

A bag contains black balls and some white balls. If the probability of drawing a black ball is 0.5 , then find the number of white balls in the bag. There are total 100 balls in the bag

A bag contains 6 white, 5 black and 4 red balls. Find the probability of getting either a white or a black ball in a single draw.

A bag contains 4 white and 5 black balls. A ball is drawn at random from the bag. Find the probability that the ball drawn 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.