IBPS PO Prelims 14 Oct 2018 Solved Paper

A box contains red, green and blue colored balls. When one ball is drawn randomly from the box, the probability that it is either green or blue is 2/3. Also, the probability that the ball drawn randomly from the box is either red or green is 3/5. When two balls are drawn one after another from the box, the probability that both balls are of green color is 1/15. Find the total number of balls in the box.