there are 2 balls in an urn, they can lee white/ black each and then a white ball is added to it, find (p[white] drawn out of it) ?

Three are two balls in an urn whose colours are not known (each ball can be either white or black). A white ball is put in the urn. A ball is drawn from the urn. Find the probability that it is white.

An urn contains two balls each of which is either white or black. A white ball is added to the urn. What is the probability of drawing a white ball from the urn now?

An urn contains two balls each of which is either white or black. A white ball is added to the urn. What is the probability of drawing a white ball from the bag now.

There are 3 bags, each containing 5 white balls and 3 black balls. Also there are 2 bags, each containing 2 white balls and 4 black balls. A white ball is drawn at random. Find the probability that this white ball is from a bag of the first group.

There are 3 bags,each containing 5 white balls and 3 black balls.Also there are 2 bags, each containing 2 white balls and 4 black balls.A white ball is drawn at random.Find the probability that this white ball is from a bag of the first group.

Urn A contains 2 white, 1 black and 3 red balls, urn B contains 3 white, 2 black and 4 red balls and urn C contains 4 white, 3 black and 2 red balls. One urn is chosen at random and 2 balls are drawn at random from the urn. If the chosen balls happen to be red and black, what is the probability that both balls come from urn B?

Urn A contains 2 white, 1 black and 3 red balls, urn B contains 3 white, 2 black and 4 red balls and urn C contains 4 white, 3 black and 2 red balls. One urn is chosen at random and 2 balls are drawn at random from the urn. If the chosen balls happen to be red and black, what is the probability that both balls come from urn B?

Three identical urns contain white and black balls. The first urn contains 2 white and 3 black balls, the second urn 3 white and 2 black balls and the third urn 1 black and 4 white balls. An urn is chosen at random and a ball is drawn from it. If the ball drawn is white, what is the probability that the first urn is chosen ?

There are 2 white , 4 black balls in urn A, In urn B, there are 5 white and 7 black balls. If one ball is randomly replaced from A and B , and a ball is drawn from B then the probability for the ball to be white one is