If 1st August 2009 was a Saturday, then what was the day of the week on 1st August 2013?

Thursday

Using Code Method :-

\(\frac{Date+Month code+Year code+Last 2 digits of yr+Leap yrs till given yr}{7}\)

( Note: Remainder of the above sum will be the code of week day }

01 Aug 2009;

01 + 0 + 06 + 09 + 02 = 18

remainder of \(\frac{18}{7}\) = 04

Therefore, the code of 04 is Wednesday + 03 = ( Saturday )

Similarly,

01 Aug 2013;

01 + 0 + 06 + 13 + 03 = 23

remainder of \(\frac{23}{7}\) = 02

Therefore, the code of 02 is Monday + 03 = ( Thursday )