4:00. Here's the process: 1. I subtracted 15 minutes from the given time of 3:45, which gave me 2:30. 2. Knowing this is 15 minutes slower than the actual time, I needed to convert the quarter past an hour into minutes, which is 15 minutes as well. 3. Adding these 15 minutes to the adjusted time of 2:30 gives me 4:00. This is the correct time, as it is a quarter past 2:45.