At a bookstore, files are sold at $9 for 1 file. For every 7 files a customer pays, an extra file will be given free.
- How much will Mrs Kong pay for 9 files?
- What is the most number of files Mr Chua can get for $144?
(a)
Number of files in one set
= 7 + 1
= 8
Cost of a set of 8 files
= 7 x 9
= $63
Number of sets
= 9 ÷ 8
= 1 r 1
Amount that Mrs Kong paid
= 1 x 63 + 1 x 9
= 63 + 9
= $72
(b)
Maximum number of sets
= 144 ÷ 63
= 2 r 9
Number of files that can be bought with remaining money
= 9 ÷ 9
= 2
Maximum number of files
= 8 x 2 + 2
= 18
Answer(s): (a) $72; (b) 18