June 25, 1987
The following is a formula/mathematical approach to solving this type of question. It is kind of cumbersome; but once acquainted, you can easily solve these types of questions.
year 1600-> 0 odd days
In every 100 years, there are 5 odd days
+300-> 5*3 = 15 odd days = 15%7= 1 odd day
Upto 1900-> 1 odd day
Upto 1986:
86/4 = 21 leap years
86-21=65 ordinary years
Every leap year: 2 odd days,
ordinary year: 1 odd day
So; 21*2+65 = 42+65=107 odd days = 107%7 = 2 odd days
So; from 1600-1986 end = 1+2 = 3 odd days
in 1987(non-leap year)
Jan=31; Feb=28; March=31; April: 30 May:31 June: 25
31+28+31+30+31+25 = 176%7 = 1 odd day
Total: 3+1=4 odd days
odd days-day
0-Sunday
1-Monday
2-Tuesday
3-Wednesday
4-Thursday
5-Friday
6-Saturday
Ans: Thursday
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June 25, 1982, fell on a Friday. On which day of the week did June 25, 1987, fall?
june 25,1983: Saturday
june 25,1984: Monday (Leap year: Feb would be 29 days- so days 2+)
june 25,1985: Tuesday
june 25,1986: Wednesday
june 25,1987: Thursday
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