The advertisement shows the cost of buying files from a stationery shop.
- Eva bought 19 files. How much did she pay?
- Tom bought 80 files. How much did he pay?
(a)
Number of sets of 15 files
= 19 ÷ 15
= 1 r 4
Cost of first 15 files
= 15 x 2.10
= $31.50
Cost of the next 4 files
= 4 x 1.90
= $7.60
Amount that Eva paid
= 31.50 + 7.60
= $39.10
(b)
Number of files that was not part of the first 15 files
= 80 - 15
= 65
Cost of first 15 files = $31.50
Cost of the next 65 files
= 65 x 1.90
= $123.50
Total cost of 80 files before an additional discount of 10% is applied
= 31.50 + 123.50
= $155
Amount that Tom paid in percent after an additional discount of 10% is applied
= 100% - 10%
= 90%
100% of the total cost of 80 files = 155
1% of the total cost of 80 files = 155 ÷ 100 = 1.55
90% of the total cost of 80 files = 90 x 1.55 = 139.50
Amount that Tom paid = $139.50
Answer(s): (a) $39.10; (b) $139.50
