If the day on 31 August 2008 was Sunday, then what was the day of the on 31 August 1993 ?

Tuesday

\(\frac{Date + Month code + Century code + Century upper year + Quotient of Upper year/4}{7}\)

\(\frac{31+2+6+8+2}{7}\)

\(\frac{49}{7}\) =  Remainder 0 means Sunday and here also Sunday is given i.e. no change 

We have to find out 31/08/1993

\(\frac{Date + Month code + Century code + Century upper year + Quotient of Upper year/4}{7}\)

\(\frac{31+2+0+93+23}{7}\)

\(\frac{149}{7}\) =  Remainder 2 means Tuesday

Therefore, Tuesday which is the correct answer.

Note:

Code for   

Mon – 1       Tues – 2       Wed – 3                      Thurs – 4     Fri – 5         Sat ­­–6                          Sun – 0

Code for    

Jan – 0         Feb – 3        Mar – 3

Apr – 6        May – 1       June – 4

July – 6        Aug – 2       Sep – 5

Oct – 0         Nov – 3       Dec – 5

Code for        1900 is 0

                    2000 is 6

                    2100 is 4

                    2200 is 2

                    2300 is 0

                    2400 is 6

                    2500 is 4   and  Likewise