20% of the books in a library were fiction books while the rest were non-fiction books. When 30% of the fiction books and 15% of the non-fiction books were borrowed, there were 1312 books left in the library. How many books were borrowed?

(Please show me your workings clearly.)

1 answer

X books in Lib.
Fiction = 0.2x books.
Non-fiction = 0.8x. books.

0.7(0.2x) + 0.85(0.8x) = 1312.
0.14x + 0.68x = 1312
0.82x = 1312
X = 1600.

0.2x = 320.
0.8x = 1280.

Books Borrowed = 1600 - 1312 = 288.