PSLE
Elijah had orange pencils and yellow pencils for sale. He sold 60 orange pencils. 40% of the pencils sold were yellow.

1. How many orange pencils and yellow pencils did Elijah sell altogether?
2. He sold 50% of his pencils. 75% of the pencils left unsold were orange. How many yellow pencils did Elijah have at first?

	Orange	Yellow	Total	Total in percent
Before	6.75 u	3.25 u	10 u	100%
Change	- 60% - 3 u	- 40% - 2 u	- 100% - 5 u	- 50%
After	75% 3.75 u	25% 1.25 u	100% 5 u	50%

40% = ⁴⁰₁₀₀ = ²₅

Total number of pencils sold = 5 u
Number of yellow pencils sold = 2 u

Number of orange pencils sold
= 5 u - 2 u
= 3 u

3 u = 60

1 u = 60 ÷ 3 = 20

Total number of pencils sold
= 5 u
= 5 x 20
= 100

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

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

Percent of the pencils left unsold that were orange = 75%
Percent of the pencils left unsold that were yellow = 100% - 75% = 25%

Number of the pencils left unsold that were yellow
= 25% x 5 u
= ²⁵₁₀₀ x 5 u
= 1.25 u

Number of yellow pencils that Elijah had at first
= 1.25 u + 2 u
= 3.25 u
= 3.25 x 20
= 65

Answer(s): (a) 100; (b) 65