Answer :

2:45 pm + 1 hour = 3:45 pm, 3:45 pm + 15 minutes = 4:00, 4:00 pm + 20 minutes = 4:20 pm, 15 minutes + 20 minutes = 35 minutes. So, Therefore, the answer is 1 hour and 35 minutes.
Bluebellsblondie
To find out the time in between a different time you can add in segments, you can add 15min to 2:45, to make it 3:00, then add 60 more minutes to make it 4:00, so now we have 75 min, then add 20 minutes to get the time to 4:20 pm, you then add up all the segments, which equal 95 minutes. In hours it would be 1 hour, and 35 minutes. Hope you understand that, of not, tell me, and ill fix it and make it more understandable.