Here is your answer- as per the official notification “the minimum qualifying marks for consideration of candidate to the selection process of various categories is as follows”…

OC - 40%

Bc- 35%

SC, ST, PH 30 %.

And does who are selected will be alloted respective departments as per their rank….and their preference…

If you want exact details then go through the below link……

Http://website.apspsc.gov.in/Doc...

Best of luck.