PSLE
Asher had a collection of rulers, foolscaps and notebooks. He had 23 rulers. 30% of his collection was foolscaps. He had 41 fewer foolscaps than notebooks.

1. How many foolscaps did Asher have?
2. Asher gave away some foolscaps. His total collection decreased by 20%. What percentage of his collection was foolscaps after that?

(a)
30% = ³⁰₁₀₀ = ³₁₀

Number of foolscaps = 3 u
Number of notebooks = 3 u + 41
Number of rulers = 23
Total number of items = 10 u

10 u = 3 u + 3 u + 41 + 23
10 u - 6 u = 64
4 u = 64

1 u = 64 ÷ 4 = 16

Number of foolscaps
= 3 u
= 3 x 16
= 48

(b)
Total number of items at first
= 10 u
= 10 x 16
= 160

Total collection in the end in percent
= 100% - 20%
= 80%

Number of items after giving away some foolscaps
= 80% x 160
= ⁸⁰₁₀₀ x 160
= 128

Number of notebooks and rulers
= 10 u - 3 u
= 7 u
= 7 x 16
= 112

Number of foolscaps left
= 128 - 112
= 16

Percentage of his collection that was foolscaps after that
= ¹⁶₁₂₈ x 100%
= 12.5%

Answer(s): (a) 48; (b) 12.5%