PSLE
Stationery Kiosks Y and Z sell rulers of four colours. The bar graphs show the number of rulers sold by each shop in August. The bar for the number blue rulers sold by Stationery Kiosk Y has not been drawn.

1. Half of the rulers sold by Stationery Kiosk Y were blue rulers. How many blue rulers did Stationery Kiosk Y sell?
2. Which colour(s) of rulers did Stationery Kiosk Y sell less than Stationery Kiosk Z? Give your answer(s) in letter(s) in alphabetical order. (Eg Blue, Red = B, R)
3. In September, Stationery Kiosk Z sold 20 less pink rulers than the number of pink rulers sold in August. What was the percentage increase in the number of pink rulers sold by Stationery Kiosk Z from August to September?

(a)
Number of purple rulers sold in Stationery Kiosk Y = 50
Number of pink rulers sold in Stationery Kiosk Y = 225
Number of orange rulers sold in Stationery Kiosk Y = 100

Since blue rulers sold in Stationery Kiosk Y is half of the rulers sold by Stationery Kiosk Y, the total of pink rulers, orange rulers and purple rulers is equal to blue rulers.

Number of blue rulers sold in Stationery Kiosk Y
= 225 + 100 + 50
= 375

(b)
Number of purple rulers sold in Stationery Kiosk Y = 50 (Less) 
Number of purple rulers sold in Stationery Kiosk Z = 250

Number of pink rulers sold in Stationery Kiosk Y = 225 (More)
Number of pink rulers sold in Stationery Kiosk Z = 25

Number of orange rulers sold in Stationery Kiosk Y = 100 (Equal)
Number of orange rulers sold in Stationery Kiosk Z = 100

Number of blue rulers sold in Stationery Kiosk Y = 375 (More) 
Number of blue rulers sold in Stationery Kiosk Z = 175 

Colour(s) of rulers that Stationery Kiosk Y sold less than Stationery Kiosk Z = Purple (P)

(c)
Percentage decrease in the number of pink rulers sold by Stationery Kiosk Z from August to September
= ²⁰₂₅ x 100%
= ⁴₅ x 100%
= 80%

Answer(s): (a) 375; (b) P; (c) 80%