If 27 September 2001 was a Thursday, then what was the day of the week on 22 October 2009?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. Thursday.
From 27 September 2001 to 27 September 2009, there are 8 years.
Leap years: 2004, 2008 (2 leap years)
Normal years: 2002, 2003, 2005, 2006, 2007, 2009 (6 normal years)
Each normal year contributes 1 extra day, and each leap year contributes 2 extra days.
So, the total extra days = (6 × 1) + (2 × 2) = 6 + 4 = 10
Since 10 mod 7 = 3, the day moves 3 days ahead from Thursday.
Thus, on 27 September 2009, the day was Sunday.
Remaining days in September: 3 days (28, 29, 30) → 3 extra days
Days in October: 22 days → 22 extra days
Total extra days = 3 + 22 = 25.
Now, 25 mod 7 = 4, so the day moves 4 days ahead from Sunday.
Sunday + 4 days = Thursday.