PSLE
Book Shops B and C sell files of four colours. The bar graphs show the number of files sold by each shop in February. The bar for the number orange files sold by Book Shop B has not been drawn.

1. Half of the files sold by Book Shop B were orange files. How many orange files did Book Shop B sell?
2. Which colour(s) of files did Book Shop B sell less than Book Shop C? Give your answer(s) in letter(s) in alphabetical order. (Eg Blue, Red = B, R)
3. In March, Book Shop C sold 5 less pink files than the number of pink files sold in February. What was the percentage increase in the number of pink files sold by Book Shop C from February to March?

(a)
Number of blue files sold in Book Shop B = 10
Number of pink files sold in Book Shop B = 40
Number of purple files sold in Book Shop B = 30

Since orange files sold in Book Shop B is half of the files sold by Book Shop B, the total of pink files, purple files and blue files is equal to orange files.

Number of orange files sold in Book Shop B
= 40 + 30 + 10
= 80

(b)
Number of blue files sold in Book Shop B = 10 (Less) 
Number of blue files sold in Book Shop C = 50

Number of pink files sold in Book Shop B = 40 (More)
Number of pink files sold in Book Shop C = 25

Number of purple files sold in Book Shop B = 30 (Equal)
Number of purple files sold in Book Shop C = 30

Number of orange files sold in Book Shop B = 80 (More) 
Number of orange files sold in Book Shop C = 20 

Colour(s) of files that Book Shop B sold less than Book Shop C = Blue (B)

(c)
Percentage decrease in the number of pink files sold by Book Shop C from February to March
= ⁵₂₅ x 100%
= ¹₅ x 100%
= 20%

Answer(s): (a) 80; (b) B; (c) 20%