Aptitude - Calendar - Discussion

I'm not understanding the relation between 1600yrs & 400yrs.

Why not we can take 1200yrs & 800yrs instead of 1600yrs & 400yrs?

Because in 100 years there are (96/4) =24 leap years and other72 years are ordinary days and as.

100 years (76 ordinary years + 24 leap years).

= (76 x 1 + 24 x 2) odd days,
= 124 odd days.
= (17 weeks + 5 days) ,
= 5 odd days.

Hence the number of odd days in 100 years = 5.

Number of odd days in 200 years = (5 x 2) = 10 -> 3 odd days.
Number of odd days in 300 years = (5 x 3) = 15 -> 1 odd days.
Number of odd days in 400 years = (5 x 4 + 1) = 21 -> 0 odd days.
Similarly, the number of odd days in all 4th centuries (400, 800, 1200 etc. ) = 0.

That is why we take 1600 & 400 instead of 1200, 800 etc. Numbers.

Well explained @Meena.

Thanks for the explanation @Rajat.

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.

Hi, I am not understanding the steps. Can anybody help me? please.

In every 400 years, there are 303 non-leap years and 97 leap years. ( 400/4 - 3 = 97 )
How? Every fourth year is a leap year, but century years (i.e, ending with 00) are considered leap years only if they are divisible by 400. So every 100th,200th and 300th years are non- leap years and the 400th year is a leap year.

The Number of odd days in every year= 365%7=1.
The Number of odd days in every leap year= 366%7=2.
The Number of odd days in every 400 years= 303*1 + 97*2 = 497.
But since 497 is a multiple of 7 (i.e, 497%7=0) , odd days is same as 0.

Now, the year 2000 has five such 400 years. So number of odd days in 2000 years= 5 * number of odd days in 400 = 5*0 = 0.

Then follow explanation for the next six years as given in solution.

Hope this helps!

What was the day in 22 march, 1989? Can anyone solve this?

Can I do this way?

28+2+1+1=32.

32÷7=remains is 4.
So the answer is,
Because in 2000-2100.
Week of days.,
2000,jan1 is sat.
So,
Fri. Sat. Sun. Mon Tue Wed Thrus
1. 2. 3. 4. 5. 6. 0

Ans is Monday.

Simple as it is,

Calculate the odd days from 2000 to 2006.

2004 is a leap year has 2 odd days.

(00+01+02+03+04+05+06) years = 1+1+1+1+2+1 odd days respectively since 2006 has it february.

= 7 % (mod) 7 = 0.

Which is sunday.