PSLE
Bookstores H and J sell post-it-pads of four colours. The bar graphs show the number of post-it-pads sold by each shop in April. The bar for the number yellow post-it-pads sold by Bookstore H has not been drawn.

1. Half of the post-it-pads sold by Bookstore H were yellow post-it-pads. How many yellow post-it-pads did Bookstore H sell?
2. Which colour(s) of post-it-pads did Bookstore H sell less than Bookstore J? Give your answer(s) in letter(s) in alphabetical order. (Eg Blue, Red = B, R)
3. In May, Bookstore J sold 15 less orange post-it-pads than the number of orange post-it-pads sold in April. What was the percentage increase in the number of orange post-it-pads sold by Bookstore J from April to May?

(a)
Number of green post-it-pads sold in Bookstore H = 40
Number of orange post-it-pads sold in Bookstore H = 90
Number of pink post-it-pads sold in Bookstore H = 70

Since yellow post-it-pads sold in Bookstore H is half of the post-it-pads sold by Bookstore H, the total of orange post-it-pads, pink post-it-pads and green post-it-pads is equal to yellow post-it-pads.

Number of yellow post-it-pads sold in Bookstore H
= 90 + 70 + 40
= 200

(b)
Number of green post-it-pads sold in Bookstore H = 40 (Less) 
Number of green post-it-pads sold in Bookstore J = 60

Number of orange post-it-pads sold in Bookstore H = 90 (More)
Number of orange post-it-pads sold in Bookstore J = 20

Number of pink post-it-pads sold in Bookstore H = 70 (Equal)
Number of pink post-it-pads sold in Bookstore J = 70

Number of yellow post-it-pads sold in Bookstore H = 200 (More) 
Number of yellow post-it-pads sold in Bookstore J = 90 

Colour(s) of post-it-pads that Bookstore H sold less than Bookstore J = Green (G)

(c)
Percentage decrease in the number of orange post-it-pads sold by Bookstore J from April to May
= ¹⁵₂₀ x 100%
= ³₄ x 100%
= 75%

Answer(s): (a) 200; (b) G; (c) 75%