Question

Calculate the cost of operating a 5.0 hp water pump for 6 hours at 8.5 cents per kilowatt-hour

Answer 1

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:

1. **Convert horsepower to kilowatts**:
\[
1 \text{ hp} \approx 0.746 \text{ kW}
\]
Therefore, a 5.0 hp pump is:
\[
5.0 \text{ hp} \times 0.746 \text{ kW/hp} = 3.73 \text{ kW}
\]

2. **Calculate the total energy consumption (in kWh)**:
The energy consumed by the pump over 6 hours is:
\[
\text{Energy (kWh)} = \text{Power (kW)} \times \text{Time (hours)}
\]
\[
\text{Energy} = 3.73 \text{ kW} \times 6 \text{ hours} = 22.38 \text{ kWh}
\]

3. **Calculate the cost of operating the pump**:
The cost is given by multiplying the energy consumed by the cost per kilowatt-hour:
\[
\text{Cost} = \text{Energy (kWh)} \times \text{Cost per kWh}
\]
\[
\text{Cost} = 22.38 \text{ kWh} \times 0.085 \text{ dollars/kWh} = 1.8983 \text{ dollars}
\]

4. **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**.