It was Sunday on Jan 1, 2006. What was the day of the week Jan 1, 2010?
Sunday
Saturday
Friday
Wednesday
Explanation:
On 31st December, 2005 it was Saturday.
Number of odd days from the year 2006 to the year 2009 = $\left(1 + 1 + 2 + 1\right)$ = 5 days.
$\therefore$ On 31st December 2009, it was Thursday.
Thus, on 1st Jan, 2010 it is Friday.