Can we ask NGOs to answer RTI based queries

I know of a few Old Age Homes in Andhra Pradesh that get grants from Ventral Government; There is reason to believe that they are misusing govt funds. But they are not as such govt institutions per-se. Can I file an RTI application to get info on: Total bed capacity, charges, occupancy details for a certain period, total charges collected etc?

Well, you can't ask directly to NGO but if its funded by Govt. fund then it comes RTI act. Its a Public Authority as defined in Sec 2(h) of the RTI Act if directly or indirectly its being funded by Government.