Cindy bought 2 laptops and 4 water heaters. Each laptop costs $280 more than each water heater. She spent 25% of her money on the water heaters.
- How much did each laptop cost?
- How much did she spend altogether?
| |
Laptops |
Water heaters |
Total |
| Number |
2 |
4 |
|
| Value |
1 u + $280 |
1 u |
|
| Total value |
2 u + $560 |
4 u |
|
Comparing amounts
spent on laptops
and water heaters |
75%
|
25% |
100% |
(a)
Amount that Cindy spent on the laptops
= 2(1 u + 280)
= 2 u + 560
Amount that Cindy spent on the water heaters
= 4 x 1 u
= 4 u
Amount that Cindy spent on the laptops in percent
= 100% - 25%
= 75%
25% → 4 u
75% → 3 x 4 u = 12 u
12 u = 2 u + 560
12 u - 2 u = 560
10 u = 560
1 u = 560 ÷ 10 = 56
Cost of each laptop
= 56 + 280
= $336
(b)
100% → 4 u + 12 u = 16 u
Amount that Cindy spent altogether
= 16 u
= 16 x 56
= $896
Answer(s): (a) $336; (b) $896
