The number of library books in a school increased by 20% after it bought new books in may. The number increased by another 20% after a bookstore donated 300 books in June. Find the number of books in the library before it bought new books in May.

Answer 1

n
after buy 1.2 n
after donation 1.2*1.2 n

300 = .2 * 1.2 n
300 = .24 n
n = 1250