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

An urn contains 6 blue and 'a' green balls. If the probability of drawing a green ball is double that of drawing a blue ball, find 'a'.

A box has come black balls and 30 white balls. If the probability of drawing of a black ball is 2/5 th the probability of drawing of a white ball, find the number of black balls in the box.

A box has 25 red and 50 black balls. Find the probability of picking (a) a red ball (b) a black ball.

A bag has white, black, and red balls. A ball is drawn at random from the bag. The probability of getting a white ball is 3/(10) and that of a black ball is 2/5 . Find the probability of getting a red ball. If the bag has 20 black balls, find the total number of balls in the bag.

A bag contains 3 red balls and 5 black balls. A ball is drawn at random from the bag. What is the probability that the ball drawn is red ?

A bag contains 3 red balls and 5 black balls. A ball is drawn at random from the bag. What is the probability that the ball drawn is not red ?

If a bag containing red and white balls, half the number of white balls is equal to one - third the number of red balls. Thrice the total number of balls by 6. How many balls of each colour does the bag contain ?

A bag contains 5 red and 3 blue balls. If 3 balls are drawn at random without replacement the probability of getting exactly one red ball is