A 12 HP motor has to be operated 8 hours / day . How much will it cost at the rate of 50 paisa / kWh in 10 days

Options

A. Rs 350/-
B. Rs.358/-
C. Rs.375/-
D. Rs.397/-

Answer

To solve the problem, we need to calculate the total cost of operating a 12 HP motor for 8 hours a day over 10 days, given the cost of electricity is 50 paisa per kWh.

### Step-by-Step Solution:

1. **Convert Horsepower to Kilowatts:**
- We know that 1 HP (Horsepower) is equivalent to 746 Watts.
- Therefore, to convert 12 HP to kilowatts:
\[ \text{Power (in kW)} = 12 \, \text{HP} \times 746 \, \text{W/HP} = 8952 \, \text{W} \]
- Since 1 kW = 1000 W, we convert watts to kilowatts:
\[ \text{Power (in kW)} = \frac{8952 \, \text{W}}{1000} = 8.952 \, \text{kW} \approx 9 \, \text{kW} \]

2. **Calculate Total Operating Hours:**
- The motor operates for 8 hours a day for 10 days:
\[ \text{Total hours} = 8 \, \text{hours/day} \times 10 \, \text{days} = 80 \, \text{hours} \]

3. **Calculate Total Energy Consumption:**
- The total energy consumed in kilowatt-hours (kWh) is given by:
\[ \text{Total energy (in kWh)} = \text{Power (in kW)} \times \text{Total hours} \]
\[ \text{Total energy} = 9 \, \text{kW} \times 80 \, \text{hours} = 720 \, \text{kWh} \]

4. **Calculate Total Cost:**
- The cost of electricity is 50 paisa per kWh, which is equivalent to 0.50 rupees per kWh.
- Therefore, the total cost can be calculated as:
\[ \text{Total cost} = \text{Total energy (in kWh)} \times \text{Cost per kWh} \]
\[ \text{Total cost} = 720 \, \text{kWh} \times 0.50 \, \text{rupees/kWh} = 360 \, \text{rupees} \]

### Final Answer:
The total cost of operating the motor for 10 days is **360 rupees**.