PSLE
Mr Tang used two printers with different printing rates for a printing job. He started Printer U at 10 23 and started Printer V two minutes later. He stopped both machines at 10 28. 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 U at the time Mr Tang started Printer V?
2. What was the difference in the number of pages printed by the two machines from 10 23 to 10 28?
3. Which printer, U or V, 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 10 25, number of pages that Printer U printed = 72

(b)
Number of pages printed by Printer U from 10 23 to 10 28
= 180

Number of pages printed by Printer V from 10 23 to 10 28
= 120

Difference in the number of pages printed by the two machines from 10 23 to 10 28
= 180 - 120
= 60

(c)
Printing rate of Printer U
= 180 ÷ 5
= 36 (Slower)

Printing rate of Printer V
= 120 ÷ 3
= 40 (Faster)

Difference in the number of pages printed by the machines in one minute
= 40 - 36
= 4

Answer(s): (a) 72; (b) 60; (c) U, 4