There are 3 bags `B_1,B_2` and `B_3` having respectively 4 white, 5 black, 3 white, 5 black and 5 white, 2 black balls. A bag is chose at random and a ball is drawn from it. Find the probability that the ball is white.

The bag A contains 3 white and 2 black balls while the bag B contains 2 white and 5 black balls. One of the bags is chosen at random and a ball is drawn from it. What is the probability that the ball is white

A bag contains 5 white and 3 black balls, a second bag contains 4 white and 5 black balls, a third bag contains 3 white and 6 black balls. A bag is selected at rendom and a ball is drawn. Find the probability that the ball is black. Do the problem assuming that the probability of choosing each bag is same.

A bag contains 5 white and 3 black balls, a second bag contains 4 white and 5 black balls, a third bag contains 3 white and 6 black balls. A bag is selected at rendom and a ball is drawn. Find the probability that the ball is black. Do the problem assuming that the probability of choosing the first bag is twice as much as choosing the second bag, which is twice as much as choosing the third bag.

A bag contains 7 white and 9 black balls. If a ball is drawn at random, what is the probability that it is white?