###Problem Statement
We want to create a billing system for a new upcoming hostel called “Travel Back Hostels”. Currently we have a few rooms with 4 beds each.
Assumptions:
- All the charges are per day:
- The cost per person is 20€.
- The whole room can be booked. In this case, for every empty bed in the room, the charge is 10€
- For every booking, there is a charge of 10€ as administration fee.
- Assume that the room availability is not an issue.
System constraints:
- At a time, you can only book 4 or less beds.