PSLE
Book Shops E and F sell files of four colours. The bar graphs show the number of files sold by each shop in October. The bar for the number blue files sold by Book Shop E has not been drawn.

1. Half of the files sold by Book Shop E were blue files. How many blue files did Book Shop E sell?
2. Which colour(s) of files 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 November, Book Shop F sold 5 less green files than the number of green files sold in October. What was the percentage increase in the number of green files sold by Book Shop F from October to November?

(a)
Number of yellow files sold in Book Shop E = 30
Number of green files sold in Book Shop E = 90
Number of purple files sold in Book Shop E = 60

Since blue files sold in Book Shop E is half of the files sold by Book Shop E, the total of green files, purple files and yellow files is equal to blue files.

Number of blue files sold in Book Shop E
= 90 + 60 + 30
= 180

(b)
Number of yellow files sold in Book Shop E = 30 (Less) 
Number of yellow files sold in Book Shop F = 70

Number of green files sold in Book Shop E = 90 (More)
Number of green files sold in Book Shop F = 10

Number of purple files sold in Book Shop E = 60 (Equal)
Number of purple files sold in Book Shop F = 60

Number of blue files sold in Book Shop E = 180 (More) 
Number of blue files sold in Book Shop F = 40 

Colour(s) of files that Book Shop E sold less than Book Shop F = Yellow (Y)

(c)
Percentage decrease in the number of green files sold by Book Shop F from October to November
= ⁵₁₀ x 100%
= ¹₂ x 100%
= 50%

Answer(s): (a) 180; (b) Y; (c) 50%