PSLE
Stationery Shops M and N sell staplers of four colours. The bar graphs show the number of staplers sold by each shop in September. The bar for the number green staplers sold by Stationery Shop M has not been drawn.

1. Half of the staplers sold by Stationery Shop M were green staplers. How many green staplers did Stationery Shop M sell?
2. Which colour(s) of staplers did Stationery Shop M sell less than Stationery Shop N? Give your answer(s) in letter(s) in alphabetical order. (Eg Blue, Red = B, R)
3. In October, Stationery Shop N sold 40 more orange staplers than the number of orange staplers sold in September. What was the percentage increase in the number of orange staplers sold by Stationery Shop N from September to October?

(a)
Number of orange staplers sold in Stationery Shop M = 90
Number of yellow staplers sold in Stationery Shop M = 40
Number of pink staplers sold in Stationery Shop M = 20

Since green staplers sold in Stationery Shop M is half of the staplers sold by Stationery Shop M, the total of orange staplers, yellow staplers and pink staplers is equal to green staplers.

Number of green staplers sold in Stationery Shop M
= 90 + 40 + 20
= 150

(b)
Number of orange staplers sold in Stationery Shop M = 90 (More)
Number of orange staplers sold in Stationery Shop N = 50

Number of yellow staplers sold in Stationery Shop M = 40 (Equal)
Number of yellow staplers sold in Stationery Shop N = 40

Number of pink staplers sold in Stationery Shop M = 20 (Less) 
Number of pink staplers sold in Stationery Shop N = 80

Number of green staplers sold in Stationery Shop M = 150 (More) 
Number of green staplers sold in Stationery Shop N = 40 

Colour(s) of staplers that Stationery Shop M sold less than Stationery Shop N = Pink (P)

(c)
Percentage increase in the number of orange staplers sold by Stationery Shop N from September to October
= ⁴⁰₅₀ x 100%
= ⁴₅ x 100%
= 80%

Answer(s): (a) 150; (b) P; (c) 80%