PSLE
Stores S and T sell post-it-pads of four colours. The bar graphs show the number of post-it-pads sold by each shop in September. The bar for the number orange post-it-pads sold by Store S has not been drawn.

1. Half of the post-it-pads sold by Store S were orange post-it-pads. How many orange post-it-pads did Store S sell?
2. Which colour(s) of post-it-pads did Store S sell less than Store T? Give your answer(s) in letter(s) in alphabetical order. (Eg Blue, Red = B, R)
3. In October, Store T sold 20 more green post-it-pads than the number of green post-it-pads sold in September. What was the percentage increase in the number of green post-it-pads sold by Store T from September to October?

(a)
Number of green post-it-pads sold in Store S = 120
Number of yellow post-it-pads sold in Store S = 120
Number of pink post-it-pads sold in Store S = 100

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

Number of orange post-it-pads sold in Store S
= 120 + 120 + 100
= 340

(b)
Number of green post-it-pads sold in Store S = 120 (More)
Number of green post-it-pads sold in Store T = 40

Number of yellow post-it-pads sold in Store S = 120 (Equal)
Number of yellow post-it-pads sold in Store T = 120

Number of pink post-it-pads sold in Store S = 100 (Less) 
Number of pink post-it-pads sold in Store T = 120

Number of orange post-it-pads sold in Store S = 340 (More) 
Number of orange post-it-pads sold in Store T = 60 

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

(c)
Percentage increase in the number of green post-it-pads sold by Store T from September to October
= ²⁰₄₀ x 100%
= ¹₂ x 100%
= 50%

Answer(s): (a) 340; (b) P; (c) 50%