PSLE
Mr Chong used two printers with different printing rates for a printing job. He started Printer X at 18 30 and started Printer Y two minutes later. He stopped both machines at 18 35. The graphs show the total number of pages printed by each printer from the start of printing.

1. How many pages had been printed by Printer X at the time Mr Chong started Printer Y?
2. What was the difference in the number of pages printed by the two machines from 18 30 to 18 35?
3. Which printer, X or Y, has a slower printing rate? What is the difference in the number of pages printed by the machines in one minute? Give your answer in this format. (Eg A, 1)

(a)
At 18 32, number of pages that Printer X printed = 144

(b)
Number of pages printed by Printer X from 18 30 to 18 35
= 360

Number of pages printed by Printer Y from 18 30 to 18 35
= 270

Difference in the number of pages printed by the two machines from 18 30 to 18 35
= 360 - 270
= 90

(c)
Printing rate of Printer X
= 360 ÷ 5
= 72 (Slower)

Printing rate of Printer Y
= 270 ÷ 3
= 90 (Faster)

Difference in the number of pages printed by the machines in one minute
= 90 - 72
= 18

Answer(s): (a) 144; (b) 90; (c) X, 18