How long are you in the hospital for an appendectomy?

OK so i was working on a project for school and on the day b4 it was due my partner for the project said she would show up to present with me the following day.The next day she did not show up and i couldn't present it all alone. That day she said she had her appendix removed but she came back 2 days later. I don't believe her because in class she wasn't in pain. She walks normal , but maybe it was true so can u answer my question (the one on the top) thanks