A bag contains 5 white and 7 black balls. Find the expectation of a man who is allowed to draw two balls from the bag and who is to receive one rupee for each black ball and two rupees for each white ball drawn.

A bag contains 5 white and 7 black balls find the expectation of a man who is alloweed to draw two balls form the bag and who is to receive one rupee for each black bal and two rupee for each white ball drawn

A bag contains 8 white and 7 black balls and another bag contains 5 white and 4 black balls. A ball is drawn at random from the first bag and put it into second bag. Now if a ball is drawn at random from the second bag. Find the probability that the ball drawn is white.

A bag contains 5 white and 4 black balls.If 3 balls are drawn at random,find the probability that at least two of them are white.

A bag contains 5 white and 4 black balls. If 3 balls are drawn at random, find the probability that at least two of them are white.

A box contains 4 white and 6 red balls if 2 balls are drawn at random find the expectation of the number of red balls

A bag contains a white and b black balls. Two players, Aa n dB alternately draw a ball from the bag, replacing the ball each time after the draw till one of them draws a white ball and wins the game. A begins the game. If the probability of A winning the game is three times that of B , then find the ratio a : b

A bag contains 3 red, 7 white, and 4 black balls. If three balls are drawn from the bag, then find the probability that all of them are of the same color.

A bag contains 5 white, 7 red and 3 black balls. If three balls are drawn one by one without replacement, find the probability that none is red.

A bag contains 5 white, 7 red and 3 black balls. If three balls are drawn one by one without replacement, find the probability that none is red.

A bag X contains 2 white and 3 black balls and another bag Y contains 4 white and 2 black balls. One bag is selected at random and a ball is drawn from it. Then the probability for the ball chosen be white is -