Does and/or mean "and and or", or "and or or&

<there's no way to know. it could be interpreted either way.>

So does it need "or both" added?

"the offer could only be taken up by someone who was over 21 or had two H's in his name, or both."

What about this one? From the apple education store

You can purchase one (1) desktop and/or one (1) notebook per academic year.

I'm guessing it means you can purchase a laptop and a desktop in one academic year, (so both)