PSLE
Bookstores L and M sell staplers of four colours. The bar graphs show the number of staplers sold by each shop in November. The bar for the number blue staplers sold by Bookstore L has not been drawn.

1. Half of the staplers sold by Bookstore L were blue staplers. How many blue staplers did Bookstore L sell?
2. Which colour(s) of staplers did Bookstore L sell less than Bookstore M? Give your answer(s) in letter(s) in alphabetical order. (Eg Blue, Red = B, R)
3. In December, Bookstore M sold 10 less purple staplers than the number of purple staplers sold in November. What was the percentage increase in the number of purple staplers sold by Bookstore M from November to December?

(a)
Number of orange staplers sold in Bookstore L = 10
Number of purple staplers sold in Bookstore L = 100
Number of green staplers sold in Bookstore L = 70

Since blue staplers sold in Bookstore L is half of the staplers sold by Bookstore L, the total of purple staplers, green staplers and orange staplers is equal to blue staplers.

Number of blue staplers sold in Bookstore L
= 100 + 70 + 10
= 180

(b)
Number of orange staplers sold in Bookstore L = 10 (Less) 
Number of orange staplers sold in Bookstore M = 70

Number of purple staplers sold in Bookstore L = 100 (More)
Number of purple staplers sold in Bookstore M = 40

Number of green staplers sold in Bookstore L = 70 (Equal)
Number of green staplers sold in Bookstore M = 70

Number of blue staplers sold in Bookstore L = 180 (More) 
Number of blue staplers sold in Bookstore M = 50 

Colour(s) of staplers that Bookstore L sold less than Bookstore M = Orange (O)

(c)
Percentage decrease in the number of purple staplers sold by Bookstore M from November to December
= ¹⁰₄₀ x 100%
= ¹₄ x 100%
= 25%

Answer(s): (a) 180; (b) O; (c) 25%