A book shop had 420 magazines. There were English, Malay and Chinese magazines in the ratio of 2 : 7 : 5. When the book shop assistant brought in another 234 new magazines, the number of English magazines was increased by 40% and the number of Malay magazines was increased by ⁶₇.

1. What was the number of Chinese magazines that the book shop assistant brought in?
2. What was the percentage increase in the number of Chinese magazines?

	English	Malay	Chinese	Total
Before	2 u	7 u	5 u	420
Change	+ 0.8 u	+ 6 u	+ ?	+ 234
After	2.8 u	13 u	6 u	654

Increase in the number of English magazines
= 40% x 2 u
= ⁴⁰₁₀₀ x 2 u
= 0.8 u

Increase in the number of Malay magazines
= ⁶₇ x 7 u
= 6 u

Total number of magazines at first
= 2 u + 7 u + 5 u
= 14 u

14 u = 420

1 u = 420 ÷ 14 = 30

Increase in the number of English and Malay magazines
= 0.8 u + 6 u
= 6.8 u
= 6.8 x 30
= 204

Number of Chinese magazines brought in
= 234 - 204
= 30 

(b)
Number of Chinese magazines at first
= 5 u
= 5 x 30
= 150

Percentage increase in Chinese magazines
= ³⁰₁₅₀ x 100%
= 20%

Answer(s): (a) 30; (b) 20%