PSLE
Book Shops R and S sell highlighters of four colours. The bar graphs show the number of highlighters sold by each shop in May. The bar for the number purple highlighters sold by Book Shop R has not been drawn.

1. Half of the highlighters sold by Book Shop R were purple highlighters. How many purple highlighters did Book Shop R sell?
2. Which colour(s) of highlighters did Book Shop R sell less than Book Shop S? Give your answer(s) in letter(s) in alphabetical order. (Eg Blue, Red = B, R)
3. In June, Book Shop S sold 15 less orange highlighters than the number of orange highlighters sold in May. What was the percentage increase in the number of orange highlighters sold by Book Shop S from May to June?

(a)
Number of green highlighters sold in Book Shop R = 80
Number of orange highlighters sold in Book Shop R = 120
Number of pink highlighters sold in Book Shop R = 160

Since purple highlighters sold in Book Shop R is half of the highlighters sold by Book Shop R, the total of orange highlighters, pink highlighters and green highlighters is equal to purple highlighters.

Number of purple highlighters sold in Book Shop R
= 120 + 160 + 80
= 360

(b)
Number of green highlighters sold in Book Shop R = 80 (Less) 
Number of green highlighters sold in Book Shop S = 140

Number of orange highlighters sold in Book Shop R = 120 (More)
Number of orange highlighters sold in Book Shop S = 20

Number of pink highlighters sold in Book Shop R = 160 (Equal)
Number of pink highlighters sold in Book Shop S = 160

Number of purple highlighters sold in Book Shop R = 360 (More) 
Number of purple highlighters sold in Book Shop S = 180 

Colour(s) of highlighters that Book Shop R sold less than Book Shop S = Green (G)

(c)
Percentage decrease in the number of orange highlighters sold by Book Shop S from May to June
= ¹⁵₂₀ x 100%
= ³₄ x 100%
= 75%

Answer(s): (a) 360; (b) G; (c) 75%