PSLE
Book Shops N and P sell notebooks of four colours. The bar graphs show the number of notebooks sold by each shop in May. The bar for the number yellow notebooks sold by Book Shop N has not been drawn.

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

(a)
Number of green notebooks sold in Book Shop N = 90
Number of purple notebooks sold in Book Shop N = 80
Number of pink notebooks sold in Book Shop N = 20

Since yellow notebooks sold in Book Shop N is half of the notebooks sold by Book Shop N, the total of green notebooks, purple notebooks and pink notebooks is equal to yellow notebooks.

Number of yellow notebooks sold in Book Shop N
= 90 + 80 + 20
= 190

(b)
Number of green notebooks sold in Book Shop N = 90 (More)
Number of green notebooks sold in Book Shop P = 50

Number of purple notebooks sold in Book Shop N = 80 (Equal)
Number of purple notebooks sold in Book Shop P = 80

Number of pink notebooks sold in Book Shop N = 20 (Less) 
Number of pink notebooks sold in Book Shop P = 80

Number of yellow notebooks sold in Book Shop N = 190 (More) 
Number of yellow notebooks sold in Book Shop P = 40 

Colour(s) of notebooks that Book Shop N sold less than Book Shop P = Pink (P)

(c)
Percentage increase in the number of green notebooks sold by Book Shop P from May to June
= ¹⁵₅₀ x 100%
= ³₁₀ x 100%
= 30%

Answer(s): (a) 190; (b) P; (c) 30%