In June 2009, on which date did the third Sunday fall?

The correct answer is Option (4) → 21 June

First find the day of the week of 31^st May 2009 by counting odd days from the start of the calendar (0 odd days means Sunday, 1 Monday, and so on). Then each later Sunday is 7 days after the one before.

• 2000 years: 0 odd days (every 400 years give 0)

• 2001 to 2008: 8 years with 2 leap years (2004, 2008): \(8+2=10\) odd days, that is 3

• January to May 2009: \(3+0+3+2+3=11\) odd days, that is 4

• Total \(=0+3+4=7\), that is 0 odd days, so 31^st May 2009 was a Sunday

• So 1^st June 2009 was a Monday and the first Sunday of June was the 7^th

• Second Sunday \(=7+7=14\)th; third Sunday \(=14+7=21\)st