If the start time is 8: 34 amd the elapsed timne is 3 hours and 18 minutes what is the end time

Forget the '34' part of 8:34 and the '18' minutes from 3 hours and 18 minutes for now.

Just add 3 hours on to 8, to get 11. Then, bring back the 34 and 18 and add them together. 34 + 12 = 52. Now put that 52 on the end of the 11, and you get 11:52 as the end time. 

11:52 is the end time.
This is how I solved it. I am not saying that this is the correct way, but it is what it is.
I set up the elapsed time as regular time; hours:minutes>> 3:18
Since the start time is 8:34, and we need to find the ending time, I can simply add the elapsed time and the starting time together.
8:34 +3:18= 11:52

Now, sometimes this won't work. There will be left over time that you'll have to add and everything, but for this situation this way worked.