Answer: Banks basically earn from the difference in the amount of what is asked from the debtor and what is remunerated to the payee.
A great hike in the need for loans is seen among people of various sections of the society for various things like- loans for buying a vehicle, loans taken by students for their higher studies, loans for personal matters, loans for buying a house, etc.
A very little percentage of money is kept by the bank as cash just in the case that the customers wish to withdraw any amount needed by them on a particular day.