Multiple choice

There were $5400$ books in a library. The ratio of the number of fiction books to the number of classics to the number of biographics was $7\colon3\colon2$. When the library acquired an additional $432$ books, the number of biographies increased by $12\%$ and the number of classics increased by $10\%$. The percentage increase in the number of fiction books is

  1. $\;8\%$
  2. $\;4\%$
  3. $\;6\%$
  4. $\;9\%$
Reveal answer Fill a bubble to check yourself
C Correct answer
AI explanation

The initial 5400 books are divided in a ratio of 7:3:2, meaning there were 3150 fiction, 1350 classics, and 900 biographies. The 432 new books include 108 new biographies (a 12% increase to 1008) and 135 new classics (a 10% increase to 1485). The remaining 189 new books are fiction, bringing the total fiction books to 3339. The percentage increase in fiction books is (189 / 3150) times 100, which equals 6%.

Keep practicing — related questions