PSLE
Cody had a collection of files, punchers and foolscaps. He had 12 files. 40% of his collection was punchers. He had 14 fewer punchers than foolscaps.

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

(a)
40% = ⁴⁰₁₀₀ = ²₅

Number of punchers = 2 u
Number of foolscaps = 2 u + 14
Number of files = 12
Total number of items = 5 u

5 u = 2 u + 2 u + 14 + 12
5 u - 4 u = 26
1 u = 26

Number of punchers
= 2 u
= 2 x 26
= 52

(b)
Total number of items at first
= 5 u
= 5 x 26
= 130

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

Number of items after giving away some punchers
= 80% x 130
= ⁸⁰₁₀₀ x 130
= 104

Number of foolscaps and files
= 5 u - 2 u
= 3 u
= 3 x 26
= 78

Number of punchers left
= 104 - 78
= 26

Percentage of his collection that was punchers after that
= ²⁶₁₀₄ x 100%
= 25%

Answer(s): (a) 52; (b) 25%