"2 hours' worth" or "2 hours worth"?
You are correct. There is no logical reason for the number (not case) to be plural with one. It's like saying a worth of one hour, so the genitive (aka possessive) case would be correct.
You are correct. There is no logical reason for the number (not case) to be plural with one. It's like saying a worth of one hour, so the genitive (aka possessive) case would be correct.