A book shop had 180 magazines. There were Malay, Chinese and English magazines in the ratio of 1 : 6 : 5. When the book shop assistant brought in another 78 new magazines, the number of Malay magazines was increased by 20% and the number of Chinese magazines was increased by ¹₃.

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

	Malay	Chinese	English	Total
Before	1 u	6 u	5 u	180
Change	+ 0.2 u	+ 2 u	+ ?	+ 78
After	1.2 u	8 u	8 u	258

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

Increase in the number of Chinese magazines
= ¹₃ x 6 u
= 2 u

Total number of magazines at first
= 1 u + 6 u + 5 u
= 12 u

12 u = 180

1 u = 180 ÷ 12 = 15

Increase in the number of Malay and Chinese magazines
= 0.2 u + 2 u
= 2.2 u
= 2.2 x 15
= 33

Number of English magazines brought in
= 78 - 33
= 45 

(b)
Number of English magazines at first
= 5 u
= 5 x 15
= 75

Percentage increase in English magazines
= ⁴⁵₇₅ x 100%
= 60%

Answer(s): (a) 45; (b) 60%