What will be the day of the week 15th August, 2010?

Goal

• Find the weekday of 15 August 2010.

Method (counting from known anchor)

Jan 1, 2010 is widely known as a Friday. Count days month-wise to Aug 15 and take mod 7.

Step 1: Days up to end of July 2010
Jan 31, Feb 28 (2010 not leap), Mar 31, Apr 30, May 31, Jun 30, Jul 31Total = 31+28+31+30+31+30+31 = 212 days

Step 2: Add 15 days of August
Cumulative days from Jan 1 to Aug 15 (inclusive of Aug 15) = 212 + 15 = 227Offset from Jan 1 (0-based) = 226226 mod 7 = 2 (since 7×32=224)Friday + 2 ⇒ Sunday

Final Answer
15 August 2010 was a Sunday.