An urn contains 'w white balls and 'b' black balls.Two players Q and R alternatively draw a ball with replacement from the urn. The player who draws a white ball first wins the game. If Q begins the game, the probability of his winning the game is

A bag contains a white and b black balls.Two players,A and B alternately draw a balls.Two 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.if the xx that of B, then find the ratio a:b

An urn contains 10 white and 5 black balls. Two balls are drawn from the urn one after the other without replacement. What is the probability that both drawn balls are white?

An urn contains 6 white and 4 black balls.A fair die is rolled and that number of balls we chosen from the urn.Find the probability that the balls selected are white.

An urn contains 3 white,4 red and 5 black balls.Two balls are drawn one by one without replacement.What is the probability that at least one ball is black?

An urn contains 3 white, 4 red and 5 black balls. Two balls re drawn one by one without replacement. What is the probability that at least one ball is black?

An urn contains 6 white and 9 black balls. Two successive draws of 4 balls are made without replacement The probability that the first draw gives all white balls and second draw gives all black balls is

An urn contains 4 white and 3 red balls. Three balls are drawn with replacement from this urn. Then, the standard deviation of the number of red balls/drawn is

An urn contains 8 white and 4 red balls. Two balls are drawn from the urn one after the other without replacement. What is the probability that both drawn balls are white ?