PSLE
Glen had a collection of markers, foolscaps and staplers. He had 259 markers. 15% of his collection was foolscaps. He had 49 fewer foolscaps than staplers.

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

(a)
15% = ¹⁵₁₀₀ = ³₂₀

Number of foolscaps = 3 u
Number of staplers = 3 u + 49
Number of markers = 259
Total number of items = 20 u

20 u = 3 u + 3 u + 49 + 259
20 u - 6 u = 308
14 u = 308

1 u = 308 ÷ 14 = 22

Number of foolscaps
= 3 u
= 3 x 22
= 66

(b)
Total number of items at first
= 20 u
= 20 x 22
= 440

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

Number of items after giving away some foolscaps
= 80% x 440
= ⁸⁰₁₀₀ x 440
= 352

Number of staplers and markers
= 20 u - 3 u
= 17 u
= 17 x 22
= 374

Number of foolscaps left
= 352 - 374
= 22

Percentage of his collection that was foolscaps after that
= ²²₃₅₂ x 100%
= 6.25%

Answer(s): (a) 66; (b) 6.25%