Aptitude - Calendar - Discussion

Month codes:

Jan- 1, Feb- 4, Mar- 4, Apr- 0, May- 2, June- 5.

July- 0, Aug- 3, Sep- 6, Oct- 1, Nov- 4, Dec- 6.

Year codes:

1500-99: 0
1600-99: 6
1700-99: 4
1800-99: 2
1900-99: 0
:
:
:
So on.......

Day codes:

Sat- 0, Sun- 1, Mon- 2, Tue- 3, Wed- 4, Thu- 5, Fri- 6.

Here,

17+05+98+24+00 = 144.

144/7 = 20+ 4 days.

Which is wednesday

Why you taken 300 years ? why not 400 years please explain in detail.

Hello Everyone.
The simple answer is:

1996+2 = 1996(leap year)+1 ordinary year+Jan to june 17th.
= 2 odd days +1 odd day+168 days.
= 2+1+0 odd days.
= 3 odd days.

i.e Wednesday.

The question is what is day of 17 june 1998?

If the year is 1998 that is mean in 100 year gets total 25 leap years if getting 25 leap in 100 year then why using 24 leap year in above comments.

Calculating leap year.
On every 4 years gets 1 leap year.
1901 to 1904 = 1 leap year.
1905 to 1908 = 1 leap year ....

Calculating odd days
I am calculating odd days from 1 jan to 17 june 1998

in jan = 31 days
feb = 28 days
march = 31 days
april = 30 days
may = 31 days
june = 17 days
------
168 days

Dividing by 7 to 168 days (7 mean 7 days in week).

168/7= 24 = 24 weeks + 0 odd days (there is any more days).

If eg., 170 /7 = 24 weeks + 2 odd days.

Only this not understood.

In above discuss why used 1900, 300, 400.

If the year is 1998.

We should have take in 1998 years.

1901 to 2000 years = total 100 years.

1901 to 1997 years = 97 years.

24 leap year + 52 weeks + 1 odd days.

We can calculate the day of week based on current date and day.

Whenever we got back one year on the same date the day of week will be one less than today's day of week.

For example today is 27th january 2014 Monday means 27th january 2013 was one day behind of Monday i.e Sunday.

If the year is leap year the day of week goes back 2 days for examples if 27th january 2013 is Sunday and the previous year 2012 is leap year so 27th january 2012 will be two day behind sunday i.e friday. If like this we calculate we have :

27th january 2013 - Sunday.
2012 - Friday 2011 - thur 2010 - wed 2009 - tue 2008 - sun.
2007 - sat 2006 - fri 2005 - thur 2004 - tue 2003 - mon .
2002 - sun 2001 - sat 2000 - thur 1999 - wed 1998 - tues.

SO now 27th January 1998 was tuesday.
To calculate : 17th june 1998 what day?

Jan Feb Mar Apr May june
5 days 28days 31d 30d 31d 17d Total = 142d
(31-27
including 27)

Now total = 142 days between 27th january 1998(Tuesday) and 17th june 1998 .

To calculate the day divide total no of days by 7 and check the remainder. If remainder is 0 it would be previous day of week. If remainder is 1 it would be same day of week. If remainder 2 it would be next day of week and so on.

So here 142/7 = 20 and remainder 2 so the day of week would be Wednesday(Next day of Tuesday).

Use doomsday algorithm :

Remember that last day of feb , 4th april, 6th july , 8th august , 10th october and 12th december will have the same day of week which is known as doomsday and we need to calculate it in the following way :

For 1900-1999 always take the anchor day as wednesday.
For 2000-2099 always take base anchor day as tuesday.

So now formula for calculating the doomsday:

Doomsday = anchor(wed for 1900-99 tue for 2000-2099) + Y/12(ignore decimal) + remainder(Y/12) + {remainder(Y/12)/4}.

Take only last two digits of the Year.

Based on the formula we have for 17th june 1998 we have:

Doomsday = wednesday + 98/12 + Remainder(98/12) + Remainder(98/12)/4.

Wednesday + 8 + 2 + 2/4.
Wednesday + 8 + 2 + 0 = wednesday + 10 = saturday.

So from the above list mentioned for the nearest doomsday we can see that 6th june is the nearest doomsday.

So 6th june will have the day Saturday.

17th june - wednesday.

Number of odd days in 97 years (24 x 2 + 73) = 121 = 2 odd days.

Can't understand this part. Can anybody explain me this part ?

How we got 24 leap year in 100 year.

It should be 100/4 = 25.

Why not 25? but 24.

Why 400 years have 0 odd day?

To find out any day of any year of date we have to go through a formula.

Always remember Code:

Jan Feb Mar Apr May June July Aug Sep Oct Nov Dec
31 (28/29) 31 30 31 30 31 31 30 31 30 31
3 (0/1) 3 2 3 2 3 3 2 3 2 3

So now today is 17/05/2014 is Saturday.(today's date)
Calculate 17/05/1998.

Now leap year(the year which is divisible by 4 or 400) coming between 1998 and 2014 is 2000,2004,2018,2012 means 4.

And year gap between 1998 to 2014 is 16.

Now add 16 to 4 and then divide with 7(days in a week)
the result gives (16+4)/7= 6

So if today is Saturday then 17/05/1998 will be Saturday - 6 = Sunday.(since we are coming to back year so we should differentiate)
Now calculate days between 17/05/1998 to 17/06/1998 is 31 day.

Now divide 7 in 31, result is 3

So if 17/05/1998 is Sunday then 17/06/1998 will be Sunday + 3= Wednesday.(Since we are going forward year we should add)