A hotel has 115 guest rooms, assume the following length of time for cleaning the following room status

- 20 minutes for a vacant room

- 15- 30 minutes for occupied stay over room

- 45 -1 hour for a departure/ arrival room.

How many housekeepers are required if they work 10 hours a day 4 days a week? How many rooms can a housekeeper service in a 10 hours shift?

Take into account off days and relief housekeepers to ensure that service continues.