What was the day of the week on 24th July 2011?

Answer: Option A

Day Codes
Saturday	0
Sunday	1
Monday	2
Tuesday	3
Wednesday	4
Thursday	5
Friday	6

Month Codes
January	1
February	4
March	4
April	0
May	2
June	5
July	0
August	3
September	6
October	1
November	4
December	6

Century Codes
1500 - 1599	0
1600 - 1699	6
1700 - 1799	4
1800 - 1899	2
1900 - 1999	0
2000 - 2099	6
2100 - 2199	4
2200 - 2299	2
2300 - 2399	0

Formula : (Date + Month code + No.of years + No.of leap year + Century code)/7
$$\begin{array}{rl}& =\frac{24+0+11+2+6}{7}\\ & =\frac{43}{7}\\ & =1\\ & =\text{Sunday}\end{array}$$