Tiffany bought 2 laptops and 7 food processors. Each laptop costs $390 more than each food processor. She spent 20% of her money on the food processors.
- How much did each laptop cost?
- How much did she spend altogether?
| |
Laptops |
Food processors |
Total |
| Number |
2 |
7 |
|
| Value |
1 u + $390 |
1 u |
|
| Total value |
2 u + $780 |
7 u |
|
Comparing amounts
spent on laptops
and food processors |
80%
|
20% |
100% |
(a)
Amount that Tiffany spent on the laptops
= 2(1 u + 390)
= 2 u + 780
Amount that Tiffany spent on the food processors
= 7 x 1 u
= 7 u
Amount that Tiffany spent on the laptops in percent
= 100% - 20%
= 80%
20% → 7 u
80% → 4 x 7 u = 28 u
28 u = 2 u + 780
28 u - 2 u = 780
26 u = 780
1 u = 780 ÷ 26 = 30
Cost of each laptop
= 30 + 390
= $420
(b)
100% → 7 u + 28 u = 35 u
Amount that Tiffany spent altogether
= 35 u
= 35 x 30
= $1050
Answer(s): (a) $420; (b) $1050
