A bag contains 5 white balls and 2 yellow balls. The number of ways of drawing 3 white balls 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.

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 white and yellow balls. The probability of choosing a white ball is 2/9 . If the total number of balls in the bag is 36, then number of yellow balls is.

Seven balls are drawn simultaneously from a bag containing 5 white and 6 green balls.The palls is of drawing 3 white and 4 green balls is

A bag contains 5 white balls, 3 black balls, 4 yellow balls. A ball is drawn from the bag, its colour is noted and put back into the bag with 5 additional balls of the same colour. The process is repeated. The probability that a yellow ball is drawn in the 1^("st") draw given that a white ball is drawn in the 2^("nd") draw is

A bag contains 3 red,4 white and 7 black balls.The probability of drawing a red or a black ball is