When both printers N and P are used, a collection of books can be printed in 3 hours. While printing, Printer N broke down. As a result, it took 2
23 hours to complete printing. If it would take Printer P 4 hours to print the collection alone,
- How long would it take to print the collection of books using only Printer N? Express your answer in hours.
- How long was Printer N used before it broke down? Express your answer in hours.
(a)
Time taken by Printer N and P:
3 h → 1 collection of books
1 h → 1 ÷ 3 =
13 collection of books
Time taken by only Printer P:
4 h → 1 collection of books
1 h → 1 ÷ 4 =
14 collection of books
Time taken by only Printer N:
1 h →
13 -
14 =
112 collection of books
1 collection of books → 1 ÷
112 = 1 x 12 = 12 h
(b)
Time taken by only Printer P:
2
23 h → 2
23 x
14 =
23 collection of books
Fraction of the collection of books to be done by Printer N
= 1 -
23=
13 Time taken by Printer N before it broke down:
13 collection of books →
13 ÷
13 =
13 x
31 = 1 h
Answer(s): (a) 12 h; (b) 1 h