A bag contains 99 black and 99 red balls. One ball is taken out at random and found to be black. It is kept aside. Another ball is now taken out. What is the probability of taking out a red ball?

A bag contains 9 blue, 4 black, 5 red and 7 white balls. One ball is taken out of the bag and found to be a red ball then again one ball is taken out at random from the remaining. What is the probability that it will be a white or a red ball?

There are one white ball and one black ball in a bag and we take a ball randomly at a time. If it is a white ball, we put three white balls back into the bag, until we get the black ball. What is the probability that we don’t get the black ball by two draws?

There are 9 green balls, 5 yellow balls, 2 white balls and 4 red balls in a bag. If someone takes out a ball from the bag without looking into it, which colour is it MOST likely to be?  RedWhiteGreenYellow

A bag I contains 4 white balls and 6 black balls. Another bag II contains 4 white balls and 3 black balls. One ball is selected at random from one of the bags and it is found to be black. Find the probability that it was drawn from bag I?

Suppose you draw a ball from the bag, note its colour and put it back. You perform this activity n times. What is the probability of getting a red ball r times out of n? In other words, what will be P(X = r)? Hint: You will need to know the number of combinations in which you can get r red balls and n−r blue balls.Note: You are not expected to know the right answer at this point. This question is given just to get you thinking in the right direction