What day of the week was 30 January 2007?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Tuesday
The day is found by counting the odd days (days left over after complete weeks) from the start of the calendar. A total of 0 odd days is Sunday, 1 is Monday, 2 is Tuesday, and so on.
First 2000 years: 0 odd days (every 400 years give 0 odd days)
Years 2001 to 2006: 5 ordinary years (1 odd day each) and 1 leap year, 2004 (2 odd days), so \(5+2=7\) odd days, that is, 0
1 to 30 January 2007: 30 days \(=4\) weeks and 2 days, so 2 odd days
Total \(0+0+2=2\) odd days, so 30 January 2007 was a Tuesday