Answer:
the correct answer is:
D. Rs. 288
Explanation:
The energy consumption (E) in kilowatt-hours (kWh) can be calculated using the formula:
[tex]\[ E = \frac{P \times t}{1000} \][/tex]
Where:
P is the power of the refrigerator in watts (400 W),
t is the operating time in hours per day (8 hours).
[tex]\[ E = \frac{400 \times 8}{1000} = 3.2 \, \text{kWh} \][/tex]
Now, to find the cost of the energy, you can multiply the energy consumption by the cost per kWh:
[tex]\[ \text{Cost} = E \times \text{Cost per kWh} \][/tex]
[tex]\[ \text{Cost} = 3.2 \, \text{kWh} \times Rs. 3.00/\text{kWh} = Rs. 9.60 \][/tex]
Now, to find the cost for 30 days, multiply by the number of days:
[tex]\[ \text{Total Cost} = \text{Cost per day} \times \text{Number of days} \][/tex]
[tex]\[ \text{Total Cost} = Rs. 9.60/day \times 30 \, \text{days} = Rs. 288 \][/tex]
Therefore, the correct answer is:
D. Rs. 288
Option D, to find the cost of operating a 400 W refrigerator for 30 days, calculate the daily kWh consumption, multiply by 30 days to find monthly kWh, and then multiply by the cost per kWh. The total cost comes to Rs. 288.
To calculate the cost of energy to operate an electric refrigerator for 30 days, we need to determine the total energy consumed in kilowatt-hours (kWh) and then multiply by the cost per kWh.
First, we find the daily energy consumption:
400 W × 8 hours/day = 3200 Wh/day = 3.2 kWh/day.
Then, we find the monthly energy consumption:
3.2 kWh/day × 30 days = 96 kWh/month.
Finally, we find the cost:
96 kWh × Rs.3.00 per kWh = Rs. 288.
Therefore, the cost of energy to operate the refrigerator for 30 days at Rs.3.00 per kWh is Rs. 288 (Option D).
