Shortcut -Calendar
Finding day of a date using a reference day.
Question:
Find the day of birth of MS Dhoni (7 July, 1981), if 31 Dec 1999 is Friday
Answer: Step 1: Number of days after 7/7/1981 in 1981 = 177
Step 2: Number of years between 1981 and 1999 = 17
Step 3: Number of leap years between 1981 and 1999 =4
Step 4: Number of days in 1999 till Dec 31 = 365
Step 5: 177 + 17 + 4 + 365= 563
Step 6: Remainder of (563/7) =3
Our reference day is Friday and the remainder is 3.
Step 7: 3 days before Friday is Tuesday.
MSD was born on Tuesday.
Note:
If there are no years in between the day in the question and reference day, step 2 and step 3 will be = 0
If a date in the future is asked, remainder number of days after the reference day will be the answer.
If remainder is 0, the day to be found out is the same day as the reference day.