Lucy bought 3 computers and 4 water heaters. Each computer costs $288 more than each water heater. She spent 25% of her money on the water heaters.
- How much did each computer cost?
- How much did she spend altogether?
| |
Computers |
Water heaters |
Total |
| Number |
3 |
4 |
|
| Value |
1 u + $288 |
1 u |
|
| Total value |
3 u + $864 |
4 u |
|
Comparing amounts
spent on computers
and water heaters |
75%
|
25% |
100% |
(a)
Amount that Lucy spent on the computers
= 3(1 u + 288)
= 3 u + 864
Amount that Lucy spent on the water heaters
= 4 x 1 u
= 4 u
Amount that Lucy spent on the computers in percent
= 100% - 25%
= 75%
25% → 4 u
75% → 3 x 4 u = 12 u
12 u = 3 u + 864
12 u - 3 u = 864
9 u = 864
1 u = 864 ÷ 9 = 96
Cost of each computer
= 96 + 288
= $384
(b)
100% → 4 u + 12 u = 16 u
Amount that Lucy spent altogether
= 16 u
= 16 x 96
= $1536
Answer(s): (a) $384; (b) $1536
