Final answer:
Leo was away for 21 hours and 30 minutes.
Step-by-step explanation:
To determine how long Leo was away for, we need to subtract the time he left from the time he returned.
First, convert the times to a 24-hour format. 13:55 becomes 13 hours and 55 minutes, and 10:45 becomes 10 hours and 45 minutes.
Next, subtract the hours and minutes separately. Subtracting the hours: 10 - 13 = -3.
Subtracting the minutes, taking into account borrowing: (-3 * 60) - 55 = -195 - 55 = -250 minutes.
To convert the negative time to positive, we can add 24 hours. -3 hours becomes 21 hours, and -250 minutes becomes 22:30.
Therefore, Leo was away for 21 hours and 30 minutes.