 Hello and welcome to the session I am Deepika here. Let's discuss a question which says, a jar contains 24 marbles, some are green and others are blue. If a marble is drawn at random from the jar, the probability that it is green is 2 upon 3. Find the number of blue balls in the jar. Now we know that the probability of an event e written as p e equal to number of outcomes favorable to e possible outcomes of the experiment. So this is a key idea behind the question. We will take the help of this key idea to solve the above question. So let's start the solution. Now according to the question a jar contains 24 marbles, some are green and others are blue. Now if marble is drawn at random from the jar is a short way of saying that all the marbles are equally likely to be drawn. Therefore the number of all possible outcomes is equal to 24. We have to find the number of blue balls in the jar. The probability of green balls in the jar is given to us in the jar and subtracted from the total number of equal to x. Note the event the ball is green. Therefore probability of a green ball that is p g is equal to outcomes is equal to x upon this as number 1. But according to the question that is the probability of a green ball is equal to 2 upon 3. Let us take this as number 2. So from 1 into 24 is equal to 2 upon 3 is equal to 2 upon 3 into 24 is equal to that is the number in the jar equal to 16. Therefore the number equal to 24 minus 16 which is equal to the above question is 8. That is the number of blue balls in the jar is 8. I hope the solution is clear to you.