Rs.40,000 per person per month is way more than good enough. Surely, we are not talking Infosys salaries here. If cheapness is a predictor of success at all, these guys have no hope. Unless they are starting hardware or biotech companies.
I think Manish's estimate is right on the mark if you are an internet startup. Things like good bandwidth or hosting or servers are way more or at least as much costly here as in Silicon Valley. Compare the rates for a 10 mbps unlimited internet connection and rented physical server space in Bangalore and silicon valley. You would probably not even make 2 3 months in Bangalore on 5L if your start up required those while 5k usd will more than cover 10 months of both in the silicon valley. Please correct me if I am wrong.