It will depend upon for which entrance exam you will prepare for , if you are preparing for CAT then above 95 percentile will be a good score , as most of the good colleges have cut offs above 95 percentile. If you want to try for IIM'S then 99 percentile without a doubt you have to get.  For any exam you prepare , your score must be above good , if you want to get admission in  good university , if you get admission in good university then you can even get a better placement opportunity.