A shop had 520 magazines. There were English, Malay and Chinese magazines in the ratio of 1 : 3 : 4. When the shop assistant brought in another 143 new magazines, the number of English magazines was increased by 20% and the number of Malay magazines was increased by ¹₃.

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

	English	Malay	Chinese	Total
Before	1 u	3 u	4 u	520
Change	+ 0.2 u	+ 1 u	+ ?	+ 143
After	1.2 u	4 u	5 u	663

Increase in the number of English magazines
= 20% x 1 u
= ²⁰₁₀₀ x 1 u
= 0.2 u

Increase in the number of Malay magazines
= ¹₃ x 3 u
= 1 u

Total number of magazines at first
= 1 u + 3 u + 4 u
= 8 u

8 u = 520

1 u = 520 ÷ 8 = 65

Increase in the number of English and Malay magazines
= 0.2 u + 1 u
= 1.2 u
= 1.2 x 65
= 78

Number of Chinese magazines brought in
= 143 - 78
= 65 

(b)
Number of Chinese magazines at first
= 4 u
= 4 x 65
= 260

Percentage increase in Chinese magazines
= ⁶⁵₂₆₀ x 100%
= 25%

Answer(s): (a) 65; (b) 25%