Find a Particular Day on the Basis of a Given Day and DateStep 1: Find the total number of odd days between the given date and the date for which the day is to be determined. Step 2: The day to be determined, will be that day of the week which is equal to the total number of odd days and this number is counted forward from the given day, in case the given day comes before the day to be determined. But, if the given day comes after the day to be determined, then the same counting is done backward from the given day. Example 1: If January 5, 1991 was Saturday, then what day of the week was it on March 4, 1992. Solution: Odd days from January 5, 1991 to January 5, 1992 = 1 Odd days from January 6, 1992 to January 31, 1992 = 5 Odd days in February 1992 = 1 Odd days from March 1, 1992 to March 4, 1992 = 4 Total Odd days = 1 + 5 + 1 + 4 = 11. When 11 is divided by 7 remainder is 4 therefore, March 4, 1992 will be 4 days after Saturday, which is Wednesday. Example 2: What day of the week was it on November 5, 1987, if it was Monday on April 4, 1988. Solution: Odd days from November 5, 1987 to April 4, 1988 = (30 - 5) days of November 1987 + 31 days of December 1987 + 31 days of January 1988 + 29 days of February 1988 + 31 days of March 1988 + 4 days of April 1988. = 25 + 31 + 31 + 29 + 31 + 4 = 151 days = 21 weeks and 4 days Total Odd days = 4 days. November 5, 1987 will be 4 days before Monday i.e. Thursday. To Find a Particular Day without Given Day and DateStep 1: Find the total number of odd days upto the date for which the day is to be determined. Step 2: Required day will be according to the following table. Basic formula for Calendar
Example 3: Find the day of the week on January 26, 1950. Solution: Odd days till January 26, 1950 = Odd days for 1600 yr + Odd days for 300 yr + Odd days for 49 yr + Odd days of 26 days of January 1950. = 0 + 1 + (12 × 2 + 37) + 5 = 67 days = 9 weeks and 4 days = 4 odd days. Therefore, January 26, 1950 is Thursday. NOTE: 49 yr have 12 leap year and 37 ordinary years. Example 4: Mahatama Gandhi was born on October 2, 1869. What was the day of the week. Solution: Odd days till the year 1868 = Odd days for 1600 yr + Odd days for 200 yr + Odd days for 68 yr = 0 + 3 + (17 × 2 + 51) = 3 + 85 = 88 days = 12 weeks and 4 days = 4 odd days. Now, total number of Odd days in year 1869 till October 2, 1869 January = 3; February = 0; March = 3; April = 2; May = 3; June = 2; July = 3; August = 3; September = 2; October = 2 23 days = 3 weeks + 2 days. Total number of odd days = 4 + 2 = 6 days. Therefore, October 2, 1869 is Saturday. |