The total cost of the notebook, the water heater and the lamp is $240. The lamp costs thrice as much as the water heater. The notebook costs twice as much as the total price of the lamp and water heater. How much more does the lamp cost than the notebook?
| Lamp |
Water Heater |
Notebook |
| 3 u |
1 u |
|
| 4 u |
8 u |
| 3 u |
1 u |
8 u |
Cost of the water heater = 1 u
Cost of the lamp = 3 u
Total cost of the water heater and the lamp
= 1 u + 3 u
= 4 u
Cost of the notebook
= 2 x 4 u
= 8 u
Total cost of the lamp, the water heater and notebook
= 8 u + 1 u + 3 u
= 12 u
12 u = 240
1 u = 240 ÷ 12 = 20
Amount that the notebook cost more than the lamp
= 8 u - 3 u
= 5 u
= 5 x 20
= $100
Answer(s): $100
