PSLE
Peter had a collection of highlighters, correction tapes and staplers. He had 252 highlighters. 15% of his collection was correction tapes. He had 14 fewer correction tapes than staplers.

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

(a)
15% = ¹⁵₁₀₀ = ³₂₀

Number of correction tapes = 3 u
Number of staplers = 3 u + 14
Number of highlighters = 252
Total number of items = 20 u

20 u = 3 u + 3 u + 14 + 252
20 u - 6 u = 266
14 u = 266

1 u = 266 ÷ 14 = 19

Number of correction tapes
= 3 u
= 3 x 19
= 57

(b)
Total number of items at first
= 20 u
= 20 x 19
= 380

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

Number of items after giving away some correction tapes
= 80% x 380
= ⁸⁰₁₀₀ x 380
= 304

Number of staplers and highlighters
= 20 u - 3 u
= 17 u
= 17 x 19
= 323

Number of correction tapes left
= 304 - 323
= 19

Percentage of his collection that was correction tapes after that
= ¹⁹₃₀₄ x 100%
= 6.25%

Answer(s): (a) 57; (b) 6.25%