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.
