Question

In 2010, a library contained a total of 11500 books in two categories - fiction and non- fiction. In 2015, the library contained a total of 12760 books in these two categories. During this period, there was 10% increase in the fiction category while there was 12% increase in the non-fiction category. How many fiction books were in the library in 2015?
1. 6600
2. 6160
3. 5500
4. 6000

Answer 1

Correct Answer - Option 1 : 6600

Calculation:

In 2010, let the number of fiction books be x

Then, the number of non-fiction books be (11500 - x)

The number of books increased from 2010 to 2015 = 12760 - 11500

⇒ The number of increased books in fiction + The number of increased books in non-fiction = 1260

⇒ x × (10/100) + (11500 - x)(12/100) = 1260

⇒ (10x/100) + 1380 - (12x/100) = 1260

⇒ 2x/100 = 1380 - 1260

⇒ x = (120 × 100)/2

⇒ x = 6000

Now in 2015, the number of fiction books = 6000 × (110/100)

⇒ 6600

∴ The number of fiction books was in the library in 2015 is 6600.