If 2 nd June 2013 is Sunday then which day was on 2 nd June 2010?

Consider from 2^nd June 2010 to 2^nd June 2013 we have total 2 non leap year and one leap year so number of odd days are 1 + 1 + 2 = 4 so 2^nd June 2010 must be 4 days back from Sunday and that day is Wednesday. From Zeller's Formula: f = k + [13 x m - 1/ 5 ] + D + [D/4] + [C/4] - 2 x C. In this case k = 2 (since 2^nd June) Month m = 4 (As march = 1, April = 2, May = 3, June = 4 ) D is the last two digit of year here D = 10 (As year is 2010) C is 1 st two digit of century here C = 20 (As year is 2010) f = 2 + [13 x 4 - 1 / 5] + 10 + [10/ 4] + [ 20/4] - 2 x 20. f = 2 + [51/5] + 10 +[2.5] + [5] - 40. f = 2 + 10 + 10 + 2 + 5 - 40 = -11 This - ve value of f can be made positive by adding multiple of 7 So f = - 11 + 14 = 3 When divided by 7 we will get remainder 3, hence number of odd days is 3, So 2^nd June 2010 is 3 days more than Monday, i.e Wednesday.