### Solution:

Concept: The cost to operate for 30 days Rs.652.8.The power of a refrigerator and the amount of time it is utilized in a day are provided in the inquiry. Additionally, the price per kWh of power utilized to run the refrigerator is provided. Therefore, using the information provided in the problem itself, we must determine the cost of running the refrigerator for 30 days.

The refrigerator's power is listed in the inquiry as 400W. The average day that the refrigerator is used is 16 hours. We are aware that power is the quantity of energy expended per unit of time. Therefore, by dividing the refrigerator's power by the number of hours it is utilized each day, we can calculate the total amount of energy consumed by the refrigerator each day.

Consequently, the refrigerator's daily energy use,

(400w) (16hrs) =6,400Wh

Now, by multiplying the energy consumption of a single day by 30, the total energy utilized in 30 such days may be determined.

Consequently, the refrigerator's 30-day energy use

=6400Wh×30= 1,92,000Wh

We obtain 192kWh when we convert the total quantity of energy utilized over the course of 30 days from Wh to kWh. As of right now, the price of energy per kWh is Rs3.40.

Consequently, the expense of running the refrigerator for 30 days

=192kWh × Rs 3.4/kWh = Rs. 652.8

Hence, the correct answer is Rs. 652.8