Aptitude - Calendar - Discussion

Ishan , Arya and Raviteja

Thanks to all u for ur such a explanation

How we gat an idea to take 1600 years and 300 years in above problem.

Step 1:[1997+1.1.1998to17.6.1998]
step2: 1997=1600+300+97=> 1600 is 0 odd days, 300 is 1 odd day
step3: calculate 97
step4:97/4= 24,=> [24-97=73]
step5:24leap year +73 ordinary year=>(24*2)+(73*1)=127
step6:127/7=17,=>17week+2 odd days
step7:1998 is an ordinary year therefore [31+28+31+30+31+17=168]
ste8:168/7=24weeks+0 odd days
step9:add all odd days we get 3 is an wednesday

Good explanation rajesh.

Muthaiyan good way of explanation.

1998=1600+300+98
1600-->0 odd days
300-->1 odd day
98 years= 24 leap yr +73 normal year

= 24*2+73*1=121 odd =121/7=2odd

Jan to June 17 =168 days =168/7= 0 odds
Total odd days=0+1+2+0=3, so its Wednesday.

A simple trick to solve calender problems for those who don't wana go for tidious concepts.

Just memorize these codes for months.

Jan=1.
Feb=4.
Mar=4.
Apr=0.
May=2.
Jun=5.
Jul=0.
Aug=3.
Sep=6.
Oct=1.
Nov=4.
Dec=6.

Days:.

S=1.
M=2.
T=3.
W=4.
Th=5.
F=6.
Sat=7 or 0.

Formula = day + month no. + (x-1900) + (x-1900) /4.
Where x = the year we have to calculate.

Eg.

17 june 1998.

Req day = 17+5+ (1998-1900) + (1998-1900) /4.
=17 + 5 + 98 + 98/4.
=17 + 5 + 98 + 24 (here do not take the digits after decimal).
=144.

Now. Devide 144 by 7.
we'll get quotient=20 and remainder=4.
So 4th day is wednesday.

This is the simplest trick. We just have to memorize the codes for months.

Thank you harsha

But tell me in case of any case if date is of 16 jan 2002. becoz here we will divide 02 by 4 which gives 0. thn code for jan =0, year code =6, adding 02+16=18.

Hence total gives=0(quotient)+0(month code)+6(year code)+18(addition of last two digits and date)=24

24/7 gives quotient gives remainder as 3 i.e tuesday. but on this date it is saturday... plz explain..

How to know how many odd days to 121 days?

Hi every one,

Here is the best solution for this for Arun and all those who want to know about concepts of using 1600 and then 300 years.


Basics :
odd days are calculated on weeks. If given 8 days, we can have 7 in a week. so here odd days=1 , where as if we have 13 days then this no will be 5.
for 121 days. 121/7=17weeks +2 days. here 2 days are odd days.

now for a year we have total of 365 day .
for leap year 366.

Step1: every ordinary year(365 days)=1 odd
Step 2: Every leap = 2 odd days.
Step 3: 100 years= 76ordinary + 24 leap year.=76+ 48=124 :: 5 odd
Step 4: year 4th century is leap year. means 100,200,300 years will have 5 odd days and 400th year will have 6 odd days.
thats coz. 400th year=25 leap +75 ordinary years=125:: 6 odd days.

Step 5: for 300 years odd days= 5+5+5=15:: 1 odd
Step 6: and for 400 years odd days =5+5+5+6=21= 0 odd days.

Step 7: Rest is explained clearly.