The image below is a schematic flow diagram of a typical oil refinery that depicts the various unit processes and the flow of intermediate product streams that occurs between the inlet crude oil feedstock and the final end products.
In order to check-in into a hotel, the person must be 21 years old.  If the person is younger than 21, then a parent or guardian can  give permission for them to check-in. 1 person found this useful.
Rented a hotel room once around 17, had to try four different places (I was paying in cash). I stayed at another hotel while doing a 1,000 mile drive. I had to stop due to bad weather, but the hotel had a rule against renting to people under 21.