Aptitude - Calendar - Discussion

How to find answer this question?

Seema remembers that her mother's birthday falls on after 21st January but before 25th January while his brother remembers that it falls after 23rd January but before 28th January. When is Seema mother birthday?

Assume 2007 starts with Sunday.

2008 starts - monday.
Since 2008 is leap year hence
2009 starts - wednesday.
2010 starts - thursday.
2011 starts- friday.
2012 starts-sat.
2012 is leap year
2013 starts- monday.
2014 starts - tuesday.
2015 starts- wednesday.
2016 starts- thursday.
2016 is leap year
2017 starts- saturday.
2018 starts - sunday
Hence 2018 will have same year as 2017.

It applies to all years:

Leap year == add 28.
1 yr after leap year== add 6.
2 yr after leap year== add 11.
3 yr after leap year == add 11.

Here 2007, nearest leap year before 2007, 2004. Therefore 2007 is 3 yrs after 2004. Therefore add 11 to 2007=2017.

Please explain in detail.

For 4n => add 28 years.

If 2004
Will same in 2004+28=2032

For 4n+1 => add 6 years.
4n+2 & 4n+3 - add 11 years.

Is this procedure is same for leap year? Please, anyone explain.

The number of extra days more than a complete week in a given period is called odd days.

Hence there are 14 days which can be of 2 weeks.

As 7 days is one week and other 7 days are another week so there are no more days which are beyond a complete week.

Therefore, the odd days are 0.

Whenever they ask for the same calender we should check whether it is a leap year or not. If it is a leap year add 28 to the given year then you will get the same calendar for leap year for non- leap years. 6 and 11 (6 is added when given year is subtracted from previous leap year u shoud get 1.

i.e ex=2005 is not a leap year..previous leap year is 2004 so (04-05=1), then add 6 because we got 1 after subtracting non-leap year with previous leap year so (2005+6=2011).

(11 is added when you subtract non-leap year to previous leap year you will get 2 nor 3).
Ex:2006 is a non-leap year, previous leap yr is 2004 so(04-06=2).
i.e 2006+11=2017.

I am not understanding this.

Please explain how 2018 will be similar to 2007?

For finding repeated calendars we used formulae of adding 28, 6, 11. for finding the past repeated calendars we have to subtract same 28, 6, 11. Am I right?