PSLE
Stores C and D sell post-it-pads of four colours. The bar graphs show the number of post-it-pads sold by each shop in November. The bar for the number yellow post-it-pads sold by Store C has not been drawn.

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

(a)
Number of pink post-it-pads sold in Store C = 20
Number of orange post-it-pads sold in Store C = 30
Number of green post-it-pads sold in Store C = 35

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

Number of yellow post-it-pads sold in Store C
= 30 + 35 + 20
= 85

(b)
Number of pink post-it-pads sold in Store C = 20 (Less) 
Number of pink post-it-pads sold in Store D = 45

Number of orange post-it-pads sold in Store C = 30 (More)
Number of orange post-it-pads sold in Store D = 20

Number of green post-it-pads sold in Store C = 35 (Equal)
Number of green post-it-pads sold in Store D = 35

Number of yellow post-it-pads sold in Store C = 85 (More) 
Number of yellow post-it-pads sold in Store D = 35 

Colour(s) of post-it-pads that Store C sold less than Store D = Pink (P)

(c)
Percentage decrease in the number of orange post-it-pads sold by Store D from November to December
= ¹⁵₂₀ x 100%
= ³₄ x 100%
= 75%

Answer(s): (a) 85; (b) P; (c) 75%