Answer:
 i got 4:35pm too
Explanation:
my workings might be more complicated and long but mb it can help others since there is more workings to refer to :)
first,
 Hr Mins
subtract 7 15 (end time)
 - 2 40 (duration)
 --------------
ans = 4 35
now, if u wonder how i got 35 mins.
 since 1Hr=60Min,
u can borrow 1 from the 7Hr(which is in Hr) to subtract the minutes.
 then, we know tht 1Hr=60Min, therefore u need to add 60mins+15mins=75mins
meaning ur working should look like this now:
  Hr Min
 6 75 (60mins+15mins)
 - 2 40 (same duration)
 -----------------
now u = 4 35pm (final answer)
can ----------------- 
normally  
subtract 
it :D  
and if some of u not sure y it is still in pm, 
7:15pm is in the evening and 4:35 is around late noon, so meaning it is still pm. {anyway, it is logic too. hv u ever seen any theater tht plays a movie from 4:35am in the morning until 7:15pm in the evening? idts, heh}