The advertisement shows the cost of buying files from a store.
- Anna bought 17 files. How much did she pay?
- Ian bought 90 files. How much did he pay?
(a)
Number of sets of 15 files
= 17 ÷ 15
= 1 r 2
Cost of first 15 files
= 15 x 2.50
= $37.50
Cost of the next 2 files
= 2 x 2.30
= $4.60
Amount that Anna paid
= 37.50 + 4.60
= $42.10
(b)
Number of files that was not part of the first 15 files
= 90 - 15
= 75
Cost of first 15 files = $37.50
Cost of the next 75 files
= 75 x 2.30
= $172.50
Total cost of 90 files before an additional discount of 4% is applied
= 37.50 + 172.50
= $210
Amount that Ian paid in percent after an additional discount of 4% is applied
= 100% - 4%
= 96%
100% of the total cost of 90 files = 210
1% of the total cost of 90 files = 210 ÷ 100 = 2.1
96% of the total cost of 90 files = 96 x 2.1 = 201.60
Amount that Ian paid = $201.60
Answer(s): (a) $42.10; (b) $201.60