A store had 900 comics. There were Chinese, English and Malay comics in the ratio of 3 : 4 : 5. When the store assistant brought in another 390 new comics, the number of Chinese comics was increased by 40% and the number of English comics was increased by ¹₂.

1. What was the number of Malay comics that the store assistant brought in?
2. What was the percentage increase in the number of Malay comics?

	Chinese	English	Malay	Total
Before	3 u	4 u	5 u	900
Change	+ 1.2 u	+ 2 u	+ ?	+ 390
After	4.2 u	6 u	7 u	1290

Increase in the number of Chinese comics
= 40% x 3 u
= ⁴⁰₁₀₀ x 3 u
= 1.2 u

Increase in the number of English comics
= ¹₂ x 4 u
= 2 u

Total number of comics at first
= 3 u + 4 u + 5 u
= 12 u

12 u = 900

1 u = 900 ÷ 12 = 75

Increase in the number of Chinese and English comics
= 1.2 u + 2 u
= 3.2 u
= 3.2 x 75
= 240

Number of Malay comics brought in
= 390 - 240
= 150 

(b)
Number of Malay comics at first
= 5 u
= 5 x 75
= 375

Percentage increase in Malay comics
= ¹⁵⁰₃₇₅ x 100%
= 40%

Answer(s): (a) 150; (b) 40%