In a factory, the output of a machine is directly proportional to the number of hours it runs and inversely proportional to the amount of energy consumption per hour. If the machine runs for 5 hours with 3 kWh per hour and produces 150 units, how many units will it produce if it runs for 8 hours with 2 kWh per hour?
Answer
360 units
The correct answer is 360 units — Find output for 8 hours and 2 kWh: units.
Step-by-step solution
- Let be the constant. Then .
- Substitute: ⇒ .
- Find output for 8 hours and 2 kWh: units.
Common mistake: Treating energy consumption as directly proportional
Concept tested: Combined direct and inverse proportion
Published · How this solution was prepared and checked
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