If 21st June 2007 was a Thursday then what was the day of the week on 21st June 2011?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Tuesday
The weekday repeats every 7 days, so only the odd days, the days left over after whole weeks, move it forward. An ordinary year of 365 days is 52 weeks + 1 day; a year that contains a 29th February has 2 odd days. Counting from 21st June 2007 one year at a time:
21 June 2007 to 21 June 2008: contains 29 February 2008, so 2 odd days
21 June 2008 to 21 June 2009: 1 odd day
21 June 2009 to 21 June 2010: 1 odd day
21 June 2010 to 21 June 2011: 1 odd day
Total \(=2+1+1+1=5\) odd days, so the day is Thursday + 5 = Tuesday