PSLE
Harry had a collection of rulers, highlighters and correction tapes. He had 14 rulers. 40% of his collection was highlighters. He had 12 fewer highlighters than correction tapes.

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

(a)
40% = ⁴⁰₁₀₀ = ²₅

Number of highlighters = 2 u
Number of correction tapes = 2 u + 12
Number of rulers = 14
Total number of items = 5 u

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

Number of highlighters
= 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 highlighters
= 80% x 130
= ⁸⁰₁₀₀ x 130
= 104

Number of correction tapes and rulers
= 5 u - 2 u
= 3 u
= 3 x 26
= 78

Number of highlighters left
= 104 - 78
= 26

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

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