A store had 935 story books. There were English, Malay and Chinese story books in the ratio of 4 : 8 : 5. When the store assistant brought in another 517 new story books, the number of English story books was increased by 60% and the number of Malay story books was increased by ¹₂.

1. What was the number of Chinese story books that the store assistant brought in?
2. What was the percentage increase in the number of Chinese story books?

	English	Malay	Chinese	Total
Before	4 u	8 u	5 u	935
Change	+ 2.4 u	+ 4 u	+ ?	+ 517
After	6.4 u	12 u	8 u	1452

Increase in the number of English story books
= 60% x 4 u
= ⁶⁰₁₀₀ x 4 u
= 2.4 u

Increase in the number of Malay story books
= ¹₂ x 8 u
= 4 u

Total number of story books at first
= 4 u + 8 u + 5 u
= 17 u

17 u = 935

1 u = 935 ÷ 17 = 55

Increase in the number of English and Malay story books
= 2.4 u + 4 u
= 6.4 u
= 6.4 x 55
= 352

Number of Chinese story books brought in
= 517 - 352
= 165 

(b)
Number of Chinese story books at first
= 5 u
= 5 x 55
= 275

Percentage increase in Chinese story books
= ¹⁶⁵₂₇₅ x 100%
= 60%

Answer(s): (a) 165; (b) 60%