Answer:
3:15
Step-by-step explanation:
Since an hour is measured every 60 minutes, we can rewrite the time 4:00 as 3:60, or 3:00 and 60 minutes. 45 minutes before this simply means that we subtract 45 minutes from this time,and 60-45=15. We can then add this time to 3:00 to get the time.
Therefore, the time is 3:15.