Explanation : By the end of centuries 400, 800, 1200, 1600, 2000,
2400, and so on, there are no extra days left. It means
that the last year 2000 was Sunday. As per convention,
the week starts with Monday and hence, the next day
after last day of year 2000, i.e., January 1, 2001, is Monday.
Explanation : There is increase of 1 day (odd day) in the subsequent
year. In case of a leap year (if the day is after February),
then there will be increase of two days.
Although 1996 is a leap year, the day in question is
in January, so there will be increase of one day. Thus,
January 1, 1996 is Monday.
Explanation : Although 1980 is a leap year, it would not have any
impact on the calculation as the date in the question is
in January month (and before 28th February). Thus, it
is assumed as a normal year. There is a gain of one day
in the next year. However, here, we will do backward
calculation, subtract 1 day from the year 1980. If it was
Saturday, then the same day in the previous year was
to be Friday
Explanation : First Wednesday of the month will be on 4th day of the
month, 2nd will be on 11th, 3rd Wednesday on 18th,
and 4th Wednesday on 25th. Now, three days after
25th, which means 25 + 4 = 29th day of the month.