The advertisement shows the cost of buying pens from a book shop.
- Pamela bought 18 pens. How much did she pay?
- Zeph bought 100 pens. How much did he pay?
(a)
Number of sets of 15 pens
= 18 ÷ 15
= 1 r 3
Cost of first 15 pens
= 15 x 2.30
= $34.50
Cost of the next 3 pens
= 3 x 2.10
= $6.30
Amount that Pamela paid
= 34.50 + 6.30
= $40.80
(b)
Number of pens that was not part of the first 15 pens
= 100 - 15
= 85
Cost of first 15 pens = $34.50
Cost of the next 85 pens
= 85 x 2.10
= $178.50
Total cost of 100 pens before an additional discount of 9% is applied
= 34.50 + 178.50
= $213
Amount that Zeph paid in percent after an additional discount of 9% is applied
= 100% - 9%
= 91%
100% of the total cost of 100 pens = 213
1% of the total cost of 100 pens = 213 ÷ 100 = 2.13
91% of the total cost of 100 pens = 91 x 2.13 = 193.83
Amount that Zeph paid = $193.83
Answer(s): (a) $40.80; (b) $193.83
