21.
How do you find the number of hours between two Time objects in Ruby?

22.
What is the purpose of the parse method for parsing dates in Ruby?

24.
What does the start_of_week method do for a Date object in Ruby?

25.
How do you find the number of minutes between two Time objects in Ruby?

26.
What is the purpose of the xmlschema method for formatting date and time strings in Ruby?

27.
How do you find the number of seconds between two Time objects in Ruby?

28.
What does the ordinal method return for a Date object in Ruby?

29.
How do you find the number of days between two Date objects in Ruby?

30.
What is the purpose of the zone method for a Date object in Ruby?