GMAT Strategy

To whom may assists,

Are the questions in the online question banks different from the questions from the Official Guide 2016 and the online GMATPrep online Pack? I have purchased the online GMATPrep a few months ago, and I am wondering are the questions different from the two online sources (Official GMAT 2016 and GMATPrep)as I have exhausted my 400 odds retired GMATPrep questions? Is it a good investment to buy the Official Guide just for the additional 900 or so question? Also, I have obtained a copy of Official Guide 2015, which does not feature the online resource, from a friend who completed his exams several months ago. Please comment. Thanks.


Sincerely,

(pgtc2009)