It's 10:30 AM and you add two hours and 30 minutes
11:30-10:00=1 hr and 30 min5:00-2:00=3 hrs
Well, if you add 30 minutes to 10:30 then you get 11:00. But you are adding 2 hours and 30 minutes to 10:30. Add two to 11:00 and you get 13:00(in military time). Or as we call 1:00 in the afternoon(pm).
