To calculate the cost of operating a 5.0 horsepower (hp) water pump for 6 hours at a rate of 8.5 cents per kilowatt-hour (kWh), we need to follow these steps:
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Convert horsepower to kilowatts: \[ 1 \text{ hp} \approx 0.746 \text{ kW} \] Therefore, a 5.0 hp pump is: \[ 5.0 \text{ hp} \times 0.746 \text{ kW/hp} = 3.73 \text{ kW} \]
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Calculate the total energy consumption (in kWh): The energy consumed by the pump over 6 hours is: \[ \text{Energy (kWh)} = \text{Power (kW)} \times \text{Time (hours)} \] \[ \text{Energy} = 3.73 \text{ kW} \times 6 \text{ hours} = 22.38 \text{ kWh} \]
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Calculate the cost of operating the pump: The cost is given by multiplying the energy consumed by the cost per kilowatt-hour: \[ \text{Cost} = \text{Energy (kWh)} \times \text{Cost per kWh} \] \[ \text{Cost} = 22.38 \text{ kWh} \times 0.085 \text{ dollars/kWh} = 1.8983 \text{ dollars} \]
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Round the result to two decimal places: The total cost of operating the pump for 6 hours is approximately: \[ \text{Cost} \approx 1.90 \text{ dollars} \]
Thus, the cost of operating the 5.0 hp water pump for 6 hours at 8.5 cents per kilowatt-hour is $1.90.