PSLE
Book Shops E and F 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 orange post-it-pads sold by Book Shop E has not been drawn.

1. Half of the post-it-pads sold by Book Shop E were orange post-it-pads. How many orange post-it-pads did Book Shop E sell?
2. Which colour(s) of post-it-pads did Book Shop E sell less than Book Shop F? Give your answer(s) in letter(s) in alphabetical order. (Eg Blue, Red = B, R)
3. In December, Book Shop F sold 50 less green post-it-pads than the number of green post-it-pads sold in November. What was the percentage increase in the number of green post-it-pads sold by Book Shop F from November to December?

(a)
Number of purple post-it-pads sold in Book Shop E = 100
Number of green post-it-pads sold in Book Shop E = 175
Number of blue post-it-pads sold in Book Shop E = 200

Since orange post-it-pads sold in Book Shop E is half of the post-it-pads sold by Book Shop E, the total of green post-it-pads, blue post-it-pads and purple post-it-pads is equal to orange post-it-pads.

Number of orange post-it-pads sold in Book Shop E
= 175 + 200 + 100
= 475

(b)
Number of purple post-it-pads sold in Book Shop E = 100 (Less) 
Number of purple post-it-pads sold in Book Shop F = 225

Number of green post-it-pads sold in Book Shop E = 175 (More)
Number of green post-it-pads sold in Book Shop F = 100

Number of blue post-it-pads sold in Book Shop E = 200 (Equal)
Number of blue post-it-pads sold in Book Shop F = 200

Number of orange post-it-pads sold in Book Shop E = 475 (More) 
Number of orange post-it-pads sold in Book Shop F = 100 

Colour(s) of post-it-pads that Book Shop E sold less than Book Shop F = Purple (P)

(c)
Percentage decrease in the number of green post-it-pads sold by Book Shop F from November to December
= ⁵⁰₁₀₀ x 100%
= ¹₂ x 100%
= 50%

Answer(s): (a) 475; (b) P; (c) 50%