The advertisement shows the cost of buying pens from a shop.
- Tiffany bought 21 pens. How much did she pay?
- Riordan bought 60 pens. How much did he pay?
(a)
Number of sets of 15 pens
= 21 ÷ 15
= 1 r 6
Cost of first 15 pens
= 15 x 3.90
= $58.50
Cost of the next 6 pens
= 6 x 3.70
= $22.20
Amount that Tiffany paid
= 58.50 + 22.20
= $80.70
(b)
Number of pens that was not part of the first 15 pens
= 60 - 15
= 45
Cost of first 15 pens = $58.50
Cost of the next 45 pens
= 45 x 3.70
= $166.50
Total cost of 60 pens before an additional discount of 10% is applied
= 58.50 + 166.50
= $225
Amount that Riordan paid in percent after an additional discount of 10% is applied
= 100% - 10%
= 90%
100% of the total cost of 60 pens = 225
1% of the total cost of 60 pens = 225 ÷ 100 = 2.25
90% of the total cost of 60 pens = 90 x 2.25 = 202.50
Amount that Riordan paid = $202.50
Answer(s): (a) $80.70; (b) $202.50
