If 21^st June 2007 was a Thursday then what was the day of the week on 21 June 2011

Tuesday

We have,

 21^st June 2007 was a Thursday

Total number of days in a normal year = 365 days

Number of odd days in a normal year = 365/7 = 1 day

Total number of days in a leap year = 366 days

Number of odd days in a leap year = 366/7 = 2 days

21^st June 2011 = Thursday + 2 (2008) + 1(2009) + 1(2010) + 1(2011) = Thursday + 5 odd days =  Tuesday