Question

It was Sunday on Jan 1, 2006. What was the day of the week on Jan 1, 2010?

• A. Sunday
• B. Saturday
• C. Friday
• D. Wednesday

Hint:

Across years: add $+1$ for each normal year and $+2$ for each leap year, then move forward that many days from the known weekday.

Answer 1

The Correct Option is C

Step 1: Span in years
Jan 1, 2006 Jan 1, 2010 spans 4 years (2006, 2007, 2008, 2009).
Step 2: Identify leap years
Among these, only 2008 is a leap year (divisible by 4, not by 100).
Step 3: Compute day shift
Each ordinary year shifts the weekday by +1; each leap year by +2.
Total shift $3\times 1 + 1\times 2 = 5$ days.
Step 4: Move 5 days ahead from Sunday
Sun Mon (a) Tue (b) Wed (c) Thu (d) \boxed{\text{Fri (5)}}.
\[ \boxed{\text{Friday (Option (c)}} \]