You can put this solution on YOUR website!
12 books be divided between A and B so that one may get 9 books and the other student 3 books.
case 1: when A will get 9 books and B will get 3 books
number of ways = 12C9 * 3C3 = 220
case 2: when A will get 3 books and B will get 9 books
number of ways = 12C3 * 9C9 = 220
total number of ways = 220 + 220 = 440
if any doubt, you are welcome to contact..