Passage

There are 3 bags containing 3 colored balls - Black, Green and White. Bag 1 contains: 15 black balls. Chances of drawing a white ball is 2/5. The ratio of number of green ball to the number of white ball is 3:4. Bag 2 contains: Number of black balls and number of white balls are equal. Number of green ball is 4/5th of the number of green ball in bag 1. The Chances of black ball is 5/14. Bag 3 contains: Number of Black Balls is (1/3)rd of the total number of black balls in Bag 1 and Bag 2 together. Number of Green ball is half of the number of white ball in bag 1. The probability of drawing a white ball is 3/7.

N black balls are transferred from bag 1 to bag 3 and (N-2) green balls are transferred from bag 3 to bag 1. One ball is picked from bag 3 and the probability that it is green is 7/37. Find N.