answer: #Person1# wants to rent a bike with a helmet. #Person2# tells #Person1# there's a deposit. #Person1# promises to bring the bike back on time.
documents: #Person1#: I'd like to rent a bike for a day. How much does it cost?
  #Person2#: It's $20 a day. A day is from 9 o'clock in the morning until 7 o'clock in the evening.
  #Person1#: So if I brought the bike back at 7:30, would I have to pay for an extra day?
  #Person2#: Yes, and there's a deposit to pay as well. It's $50. Then when you bring the bike back, we'll give you back the $50. But if you didn't bring the bike back before 7:00 PM, we'd keep the money of course.
  #Person1#: Well. You don't need to worry. I'll surely bring the bike back at 5 o'clock. Do you have helmets, by the way?
  #Person2#: Of course. It's free to rent a helmet. Let's go and choose a bike and helmet for you.