Seeing as i have certainly used addy to pursue academic purposes, it will greatly help you study unless you take too much. 10mg, depending on how often you take it may or may not be the amount you need. If your a small person, then maybe try 10, to make sure you don't feel too funny but i wouldnt do more than 20mg for something like studying. This will be a good amount to help you feel and stay focused and retain info, but not crack out.
Addy is bad for you though if you do it a lot or consistently, no matter the dosage. If you resort to this method, just use wisely! Its bad for the heart and can be addictive because of the amphetamine.
PS: I would NOT recommend smoking pot before studying lol being a pot user, i will say unless your going to an open discussion class or lecture class....this will not help you retain information and not smoking pot while on addy because that will increase your addy high and that will also be counterproductive to your cause.