PSLE
Stores J and K sell notebooks of four colours. The bar graphs show the number of notebooks sold by each shop in September. The bar for the number purple notebooks sold by Store J has not been drawn.

1. Half of the notebooks sold by Store J were purple notebooks. How many purple notebooks did Store J sell?
2. Which colour(s) of notebooks did Store J sell less than Store K? Give your answer(s) in letter(s) in alphabetical order. (Eg Blue, Red = B, R)
3. In October, Store K sold 30 more orange notebooks than the number of orange notebooks sold in September. What was the percentage increase in the number of orange notebooks sold by Store K from September to October?

(a)
Number of orange notebooks sold in Store J = 150
Number of pink notebooks sold in Store J = 200
Number of yellow notebooks sold in Store J = 75

Since purple notebooks sold in Store J is half of the notebooks sold by Store J, the total of orange notebooks, pink notebooks and yellow notebooks is equal to purple notebooks.

Number of purple notebooks sold in Store J
= 150 + 200 + 75
= 425

(b)
Number of orange notebooks sold in Store J = 150 (More)
Number of orange notebooks sold in Store K = 75

Number of pink notebooks sold in Store J = 200 (Equal)
Number of pink notebooks sold in Store K = 200

Number of yellow notebooks sold in Store J = 75 (Less) 
Number of yellow notebooks sold in Store K = 175

Number of purple notebooks sold in Store J = 425 (More) 
Number of purple notebooks sold in Store K = 250 

Colour(s) of notebooks that Store J sold less than Store K = Yellow (Y)

(c)
Percentage increase in the number of orange notebooks sold by Store K from September to October
= ³⁰₇₅ x 100%
= ²₅ x 100%
= 40%

Answer(s): (a) 425; (b) Y; (c) 40%