 Hello and welcome to the session I am Deepika and I am going to help you to solve the following question. The question says a bag contains 5 red balls and some blue balls. If the probability of drawing a blue ball from the bag is thrice that of a red ball, find the number of blue balls in the bag. So let's start the solution. Now we have the number of red balls in the bag is equal to 5. So let the number of blue balls in the bag is equal to x. Therefore the total number of balls in the bag is equal to 5 plus x. Now probability of drawing a red ball is equal to number of red balls which is 5 upon total number of balls in the bag which is 5 plus x. And probability of drawing a blue ball is equal to number of blue balls in the bag which is x upon total number of balls in the bag which is 5 plus x. Now according to the given question the probability of drawing a blue ball from the bag is thrice that of a red ball. So according to the given question we have probability of drawing a blue ball which is x over 5 plus x is equal to 3 into probability of drawing a red ball which is 5 over 5 plus x. So we have x over 5 plus x is equal to 3 into 5 over 5 plus x or x over 5 plus x is equal to 15 over 5 plus x. So this implies x is equal to 15. Therefore the number of blue balls in the bag is equal to 15. Hence the answer for the above question is 15. This completes our session. I hope the solution is clear to you while you have a nice day.