The total cost of the laptop, the speaker and the water heater is $400. The water heater costs four times as much as the speaker. The laptop costs thrice as much as the total price of the water heater and speaker. How much less does the water heater cost than the laptop?
| Water Heater |
Speaker |
Laptop |
| 4 u |
1 u |
|
| 5 u |
15 u |
| 4 u |
1 u |
15 u |
Cost of the speaker = 1 u
Cost of the water heater = 4 u
Total cost of the speaker and the water heater
= 1 u + 4 u
= 5 u
Cost of the laptop
= 3 x 5 u
= 15 u
Total cost of the water heater, the speaker and laptop
= 15 u + 1 u + 4 u
= 20 u
20 u = 400
1 u = 400 ÷ 20 = 20
Amount that the water heater cost less than the laptop
= 15 u - 4 u
= 11 u
= 11 x 20
= $220
Answer(s): $220
