Answer:
The watch loses 5 seconds per hour. It is 5 minutes slow. 5 minutes is 300 seconds(5 x 60). 300 seconds therefore represents 300/5 hours=60 hours. From Tuesday 10.30 AM backwards 60 hours(2 1/2 days) brings you to 10.30 PM on Sunday evening as the date and time the watch was last set.
Explanation: