PSLE
Daniel had purple staplers and pink staplers for sale. He sold 700 purple staplers. 30% of the staplers sold were pink.

1. How many purple staplers and pink staplers did Daniel sell altogether?
2. He sold 50% of his staplers. 75% of the staplers left unsold were purple. How many pink staplers did Daniel have at first?

	Purple	Pink	Total	Total in percent
Before	14.5 u	5.5 u	20 u	100%
Change	- 70% - 7 u	- 30% - 3 u	- 100% - 10 u	- 50%
After	75% 7.5 u	25% 2.5 u	100% 10 u	50%

30% = ³⁰₁₀₀ = ³₁₀

Total number of staplers sold = 10 u
Number of pink staplers sold = 3 u

Number of purple staplers sold
= 10 u - 3 u
= 7 u

7 u = 700

1 u = 700 ÷ 7 = 100

Total number of staplers sold
= 10 u
= 10 x 100
= 1000

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

50% of the staplers that were sold = 10 u
50% of the staplers that were left unsold = 10 u

Percent of the staplers left unsold that were purple = 75%
Percent of the staplers left unsold that were pink = 100% - 75% = 25%

Number of the staplers left unsold that were pink
= 25% x 10 u
= ²⁵₁₀₀ x 10 u
= 2.5 u

Number of pink staplers that Daniel had at first
= 2.5 u + 3 u
= 5.5 u
= 5.5 x 100
= 550

Answer(s): (a) 1000; (b) 550