PSLE
Fabian had silver notebooks and gold notebooks for sale. He sold 120 silver notebooks. 40% of the notebooks sold were gold.

1. How many silver notebooks and gold notebooks did Fabian sell altogether?
2. He sold 50% of his notebooks. 60% of the notebooks left unsold were silver. How many gold notebooks did Fabian have at first?

	Silver	Gold	Total	Total in percent
Before	6 u	4 u	10 u	100%
Change	- 60% - 3 u	- 40% - 2 u	- 100% - 5 u	- 50%
After	60% 3 u	40% 2 u	100% 5 u	50%

40% = ⁴⁰₁₀₀ = ²₅

Total number of notebooks sold = 5 u
Number of gold notebooks sold = 2 u

Number of silver notebooks sold
= 5 u - 2 u
= 3 u

3 u = 120

1 u = 120 ÷ 3 = 40

Total number of notebooks sold
= 5 u
= 5 x 40
= 200

(b)
Percent of the notebooks left unsold
= 100% - 50%
= 50%

50% of the notebooks that were sold = 5 u
50% of the notebooks that were left unsold = 5 u

Percent of the notebooks left unsold that were silver = 60%
Percent of the notebooks left unsold that were gold = 100% - 60% = 40%

Number of the notebooks left unsold that were gold
= 40% x 5 u
= ⁴⁰₁₀₀ x 5 u
= 2 u

Number of gold notebooks that Fabian had at first
= 2 u + 2 u
= 4 u
= 4 x 40
= 160

Answer(s): (a) 200; (b) 160