It was a sunday on 9th Nov, 2006. What day of the week was it on 9th Nov, 2005?
Saturday
The year 2005 is an ordinary year. So, it has 1 odd day.
So, the day on 9th Nov, 2006 will be 1 day beyond the day on 9th Nov, 2005.
9th Nov, 2006 is Sunday.
∴9th Nov, 2005 is Saturday.