Aptitude - Calendar - Discussion

Important Points:

An ordinary year has 365 days = 52 weeks and 1 odd day.

A leap year has 366 days = 52 weeks and 2 odd days.

Century = 76 Ordinary years + 24 Leap years.

Century contain 5 odd days.

200 years contain 3 odd days.

300 years contain 1 odd day.

400 years contain 0 odd days.

Last day of a century cannot be Tuesday, Thursday or Saturday.

First day of a century must be Monday, Tuesday, Thursday or Saturday.


Explanation:

100 years = 76 ordinary years + 24 leap years

= 76 odd days + 24 x 2 odd days

= 124 odd days = 17 weeks + 5 days

100 years contain 5 odd days.


No. of odd days in first century = 5

Last day of first century is Friday.


No. of odd days in two centuries = 3

Wednesday is the last day.


No. of odd days in three centuries = 1

Monday is the last day.


No. of odd days in four centuries = 0

Sunday is the last day.


Since the order is continually kept in successive cycles, the last day of a century cannot be Tuesday, Thursday or Saturday.

So, the last day of a century should be Sunday, Monday, Wednesday or Friday.

Therefore, the first day of a century must be Monday, Tuesday, Thursday or Saturday.


Working Rules:

Working rule to find the day of the week on a particular date when reference day is given:

Step 1: Find the net number of odd days for the period between the reference date and the given date (exclude the reference day but count the given date for counting the number of net odd days).

Step 2: The day of the week on the particular date is equal to the number of net odd days ahead of the reference day (if the reference day was before this date) but behind the reference day (if this date was behind the reference day).

Working rule to find the day of the week on a particular date when no reference day is given


Step 1: Count the net number of odd days on the given date

Step 2: Write:

For 0 odd days " Sunday

For 1 odd day " Monday

For 2 odd days " Tuesday

. . . .

. . . .

. . . .

For 6 odd days " Saturday


Examples:

1. If 11th January 1997 was a Sunday then what day of the week was on 10th January 2000?

Sol: Total number of days between 11th January 1997 and 10th January 2000

= (365 " 11) in 1997 + 365 in 1998 + 365 in 1999 + 10 days in 2000

= (50 weeks + 4 odd days) + (52 weeks + 1 odd day) +

(52 weeks + 1 odd day) + (1 week + 3 odd days)

Total number of odd days = 4 + 1 + 1 + 3 = 9 days = 1 week + 2 days

Hence, 10th January, 2000 would be 2 days ahead of Sunday i.e. it was on Tuesday.


2. What day of the week was on 10th June 2008?

Sol: 10th June 2008 = 2007 years + First 5 months up to May 2008 + 10 days of June

2000 years have 0 odd days.

Remaining 7 years has 1 leap year and 6 ordinary years2 + 6 = 8 odd days

So, 2007 years have 8 odd days.

No. of odd days from 1st January 2008 to 31st May 2008 = 3+1+3+2+3 = 12

10 days of June has 3 odd days.

Total number of odd days = 8+12+3 = 23


23 odd days = 3 weeks + 2 odd days.

Hence, 10th June, 2008 was Tuesday.

Simple solution here is the trick. Just need to follow this step, guys this type of questions is very easy. But you.

Need to be perfect while solving.

First of all.

Month code.

Jan - 1.
Feb - 4.
Mar - 4.
Apr - 0.
May - 2.
June - 5.
July - 0.
August - 3.
September - 6.
October - 1.
November - 4.
December - 6.

Day code:

Sun - 1.
Mon - 2.
Tues - 4.
Wed - 5.
Thur - 7.
Fri - 8.
Sat - no decimal.

Now lets solve one example.

Example :- My DOB is 15th august 1989.

Step 1 - Take the last two digit of your birth year. Here in my case it is ' 89 '.

Step 2 - Now multiply the last two digit of birth year by "5".

89 x 5 = 445.

Step 3 - Now divide the result by "4".

445/4 = 111.25.

Step 4 - in this step remove the part of the result after decimal (RHS).

111.25 - remove 25.

Now we are having 111.

Step 5 - Now add the month code given above to this.

Month code for august is '3'.

So after adding.

3 + 111 = 114.

Step 6 - Now add the date of your birth. To this.

114 + 15 (15th august) = 129.

Step 7 - Don't worry this is the last step. ;-) ;-) ha ha.

Now finally divide this by '7'.

129/7 = 18.428.

Now we have got the final answer 18.428.

Now very important thing to remember. You have to look.

Upon the next digit after the decimal (right hand side).

In 18.428 the digit after the decimal is '4'.

Now go to the day code given above and see there '4' is for Tuesday. So answer is Tuesday.

15th august 1989 was a Tuesday.

Hope you all have understood this trick.

Note :- 1) I f in the " step 7 " you get no decimal than it is definitely " Saturday ". (see the day code column I have Already mentioned there " Saturday - no decimal ").

2) what to do if the date given is from leap year. Do the all step as it is, just.

Consider the earlier day.

Ex:- If at the last step you get " Friday " then Thursday will be your answer.

That's it. Just practice this steps you'll be perfect. Hope you all like this.

Please explain why you consider 1600 is zero odd days?

Hi, friends here I'm giving the simple trick to slice these type of questions:

First Remind these codes they are : Monthly Codes

Jan = 0 , Feb = 3 , March = 3
April= 6 , May = 1, June = 4
July = 6 , Aug = 2 , Sept = 5
Octo= 0 , Nov = 3, Dec = 5


Century codes :

Please observe carefully and Apply the century code for the question

1600 = 6 1500 = 0
1700 = 4. 1400 = 4
1800 = 2 1300 = 2
1900 = 0 1200 = 6
Again it repeats
2000 = 6
2100 = 4
2200 = 2
2300 = 0

Weekly codes :

Sun - 0
M-. 1
T- 2
W. 3
Th 4
F-. 5
Sa. 6

Question : 28- may -2016?

Here to get the answer apply a format
First,
28 is the date.
May code - 1.
Century code - 6.
Last 2 digits - 06.
And add to 2 last digits by 4.. that means 06 by 4 take the quotient that is 06/4 = quotient= 1 add to the above format

Format:
28+1+6+6+1 = 42

And lastly, divide by 7
42/7 = 6.

Here take remainder when we are divide by 7 remainder will be 0.
Then 0 is Called Sunday.

Why we are using 0+0+6+1 in it? Explain it briefly.

I can't get this question. Please explain easily.

I AM UNABLE TO GET THE SOLUTION OF THIS TYPE OF QUESTION. PLEASE HELP ME..
AND what do they mean by odd days.
please explain in a more better way if you can.

What is meant by odd days?

How can I calculate that 5 yrs/ then whats meaning of odd days?

How can u say 1600 years as 0 odd days?