How many hours should a high school senior work?

If you decide to go into the DECA program, you attend school for half a day and work for half a day, so that would give you 20 hours a week plus you can work on your own time for another 20 and get a full 40 hours a week if you can fit that into your schedule, but consider what you want to do and don't neglect a good education. Good luck.