Final answer:
The total electricity tariff for using 75 bulbs and 30 fans over a period of 3 months, with the cost of 1 unit being Rs. 9.75, is Rs. 28036.12.
Step-by-step explanation:
The question is asking to calculate the total electricity cost for running 75 bulbs of 30 W each for 7 hours daily and 30 fans of 60 W each for 9 hours daily over a period of 3 months, given that the cost of 1 unit of electricity is Rs. 9.75. To solve this, we need to calculate the total energy consumption in kilowatt-hours (kWh) and then multiply by the cost per unit.
Firstly, we calculate the daily energy consumption for the bulbs:
- Total power usage by bulbs per day = 75 bulbs × 30 W each = 2250 W
- Total energy consumption by bulbs per day = (2250 W / 1000) × 7 hours = 15.75 kWh
Then, we calculate the daily energy consumption for the fans:
- Total power usage by fans per day = 30 fans × 60 W each = 1800 W
- Total energy consumption by fans per day = (1800 W / 1000) × 9 hours = 16.2 kWh
The total daily energy consumption for bulbs and fans combined is:
15.75 kWh (bulbs) + 16.2 kWh (fans) = 31.95 kWh per day
Now, we need to calculate the energy consumption for 3 months. Assuming each month has 30 days, the total number of days is 90:
Total energy consumption for 3 months = 31.95 kWh per day × 90 days = 2875.5 kWh
Finally, we calculate the total tariff:
Total cost = 2875.5 kWh × Rs. 9.75 per kWh = Rs. 28036.12