I am looking for good information on Permutation and Combination(websites). In my practice exams (GMAT), I get a score, ranging from 680-740 (old ETS papers). I am sure, if I need to touch 50s in the quant, i will be encountered with questions on Permutation and Combination (which I have ignored in my preparation). Some of my frnds (well of them who took gmat) said, that a person who touches 48+ in quant in bound to get 2 to 3 combinations and permutation questions. I do not want that type of a quesion coming in the start and I fail to answer it, which will effect my overall score. Please, can someone suggest me a site which gives info on Permutation and Combination?.
Giving another SHOT