CALENDARS

To solve the calendar related problems, you should know following basic concepts.

Ordinary Year:

     An ordinary year has 365 days. The year which is not a leap year is called an ordinary years. Example: 1999,2017

Leap Year:

     A leap year has 366 days.

        (i) Every year divisible by 4 is a leap year, if it is not a century.

        (ii) Every 4th century is a leap year and no other century is a leap year.

        Example:1948, 2004,1200, 1600, 2000  is a leap year.

                       1800, 2100 is a not a leap year.

Odd Day calculation:

     Number of days more than the complete weeks are called odd days.

     For Ordinary Year       = 365 days       = 52 weeks     + 1 day  (i.e 1 odd day)

     For Leap Year              = 366 days      = 52 weeks      + 2 days (i.e 2 odd days)

     For 100 Years

     100 Years = 76 ordinary Years + 24 Leap Years         =(76 x 1)+ (24 x 2) = 124  odd days

                           = 17 weeks + 5 days   = 5 odd days

     For 200 Years   =  5 x 2 =  10 = 3 odd days

     For 300 Years    = 5 x 3 = 15 = 1 odd days

     For 400 Years    = 5 x 4 +1=21  = 0 odd days

Key Points:

Last day of any century can’t be Tuesday, Thursday and Saturday.

Last day of any century leap year is SUNDAY.

1. Same Calendar Problem
2. Finding a day when another day is given
3. Fining a day when another day is not given

1 .The calendar 2006 will be same for the year

a) 2015 b) 2017   c)2009  d)2018

Answer: b)2017

Explanation:

Count the number of odd days from the year 2007 onwards to get the sum equal to 0 odd day.

2006  -1,    2007 -1,     2008 -2,     2009-1,    2010-1,    2011-1,   2012-2,   2013-1, 2014-1,   2015-1,  2016-2,  2017-1

Total odd days from 2007-2017 = 14 days= 0 odd day

Hence 2017 calendar will be same as 2006.

2. If 1^st Jan 2005 is Saturday then what will be 1^st Jan 2008?

a)Monday b)Friday c)Tuesday d)Saturday

Answer: c)Tuesday

Explanation:

On 31st December it was Friday.Number of Odd days between 2006 and 2008 = (1+1)=2days

Then December 31st 2007 will be Monday then 1st Jan 2008 will be Tuesday.

3. What will be the day on week 4th April 2001?

a)Sunday b)Monday c)Wednesday d)Friday

Answer: c) Wednesday

Explanation:

April 4th 2001 =(2000 years+Period of 1.1.2001 to 4.4.2001)

Odd days in 2000 years = 0 days

From January to April 4

Total no.of.days:31+28+31+4=94 days =(13 weeks +3 days)=3 odd days

So the day will be Wednesday

Thus in this post we learned about the concepts of calendar and the problems based on calendar concept with examples.