reed's bookstore is open 9 hours each day. it opens at 9:30a.m. when does it close? i know the answer but i don't know how to show my work. please help.

Two ways to do it.
12:00 noon - 9:30 = 2:30 hours in the morning. That leaves
6:00 hours - 2:30 minutes for the afternoon and that = 3:30 hours.
Then 12:00 noon + 3:30 hours = 3:30 pm.

Second way. Do you know how to tell time by the 24 hour system? If so, then
9:30 + 6:00 = 15:30
and 15:30 on the 24 hour system is 3:30 pm.
I hope this helps.

thank you.

You're welcome! I'm glad I could help explain how to solve the problem. If you have any more questions, feel free to ask!