can agreement date be back dated

passionate (ca final article ) (45 Points)

09 March 2010  

can agreement date be back dated from purchase of stamp date? e.g. i purchased stamp paper on 10march can i enter agreement of articleship starting from 10 feb? 

if yes, how many months back date is valid.... i think its allowed sum says 1 month, sum says 3..pls clarify?...