First of all a BIG thank you to GREMAT for having come up with this doc. I have made some minor changes to this doc (see attachment) that I feel would benefit one and all.
I have segregated all PS and DS questions so that one can practice either type separately. Also, the ans are hidden to make the practice more meaningful (by not looking at the ans). Anytime you want to look at ans, just highlight the text between the dotted lines, go to Format -> Font -> Click Font tab -> Uncheck Hidden to display the ans for that particular problem.
If you do not want this option for none of the problems, simply hit Ctrl + A, go to Format -> Font -> Click Font tab -> Uncheck Hidden to display answers for all questions.
Hope this helps..