PSLE
Lee had a collection of correction tapes, markers and post-it pads. He had 230 correction tapes. 15% of his collection was markers. He had 36 fewer markers than post-it pads.

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

(a)
15% = ¹⁵₁₀₀ = ³₂₀

Number of markers = 3 u
Number of post-it pads = 3 u + 36
Number of correction tapes = 230
Total number of items = 20 u

20 u = 3 u + 3 u + 36 + 230
20 u - 6 u = 266
14 u = 266

1 u = 266 ÷ 14 = 19

Number of markers
= 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 markers
= 80% x 380
= ⁸⁰₁₀₀ x 380
= 304

Number of post-it pads and correction tapes
= 20 u - 3 u
= 17 u
= 17 x 19
= 323

Number of markers left
= 304 - 323
= 19

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

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