Aptitude - Calendar - Discussion

Hello everybody ,
You must know some codes first.

Years, Days, Century code(for every 400 years ).
Jan-0, sun-0, 0:99-6.
Feb-3, mon-1, 1:199-4.
Mar-3, tue-2, 2:299-2.
Apr-6, wed-3, 3:399-0.
may-1, thr-4,
Jun-4, fri-5,
Jul-6, sat-6,
Aug-2.
Sep-5.
Oct-0.
Nov-3.
Dec-5.

Now formula is ,

Day = (Date+month code+no.of years+no.of leap years + century code)/(7).

In the given question 15th Aug 2010.

Day = (15+2+10+2+6)/7 = 7/7 = 0. Which is 'Sunday'. :).

My dear how take 1600 years and 400 years And how leap year multiply by 2X2?

friends, Let me introduce a technique which is used to find any day with any date from 1900 to 2999.

This is called doomsday technique;

doomsday means:

Last day of feb.

4th april(04.04)
6th june (06.06)
8th august(08.08)
10th oct(10.10)
12th dec(12.12)

To find doomsday of any year we should do,

anchor+(y/12)+remainder(y/12)+(remainder(y/12)/4).

For any period from 1900 to 1999 anchor = 3(wednesday).
For any period from 2000 to 2999 anchor = 2(tuesday) .
y means last 2 digits of the given year.

Now, our question here is to find the day on 15.08.2010
So,anchor=2, y=10.

2+(10/12)+rem(10/12)+(rem(10/12)/4).
2+0+10+2 =14.
14/7 = 0 so 0 odd days.
So dooms day is sunday.

For our question aug 8 is nearer. So, 08.08.2010 is surely sunday
add another 7 to 0 odd days. because 8+7=15. i.e 8th aug + 7 days = 15th aug.

0+7 odd days=7 odd days=7/7=0.

So the day is Sunday.

August 15th,2010 = (2000) +
(from 2001 to 2009) +
(from 1st January 2010 to 15th august 2010).

Odd Days in 2000 = 0.
Odd Days (from 2001 to 2009) = 2 Leap Year+7 Ordinary Year
= (2*2)+(7*1)
= 11%7 = 4 Odd Days.

Odd Days (from 1st January 2010 to 15th august 2010):

Jan = 31.
Feb = 28(not a leap year).
mar = 31.
Apr = 30.
May = 31.
Jun = 30.
Jul = 31.
Aug = 15.
===========
Tot = 227.
===========

Find Odd Days : 227%7 = 3(Odd Days).

Answer : Add all Odd Days = 0+4+3 = 7.

Notes for Odd Days : Number of days more than a complete week is
called as "Odd Days".

So, you have to divide 7 by 7.

Final Answer = 7%7 = 0 (Sunday)

What the day on 16 may 1992?

1992 = (1991)+(days between 1/1/1992 to 16/5/1992).
1600 = 0.
300 = 1.

91 = (22 leap)+(69 ordinary day).
= (22*2)+(69*1).
= 113 days.

= 16 weeks 1 day = 1 odd day.

Total 1991 yrs = 0+1+1 = 2 odd days.

jan feb mar april may
31 28 31 30 16 = 136 days.

= 19 weeks 3 days.

= 3 odd days.

Total till 16 may 1992 = 2+3 = 5.
5 = FRIDAY.
But in actual calendar it's SATURDAY. CAN I get the correct method to find it?

How can I know 9 years = (7 ordinary years +2 leap years).

How to find odd years in 100 years, 80 years or so.... Is their any formula to find it rather to go year by year calculation.

In 2nd and 3rd step, from where does that 1600 and 400 years came?

Why you are taken one time 1600, 400 or 1600, 300 in sum it's not possible to me to understand please help me?

Friends can you explain 7%7=0 taken as sunday how?