As a young person (no kids, mind you!) I lived in the NYC metro on just under 30k yearly. I ate lots of soup, but it kind of worked.
Now, I had a handshake deal with the landlords (Roomie and landlords shared an ethnicity, deals abounded!), shared my apartment with another woman, worked from 7am-11pm 4 days a week and half a weekend, bought the cheapest everything, rolled into the gas station on fumes every payday and never had new clothes, but it worked.
I can imagine a family doing it on about double that?
I am always amazed by what people think about the NYC metro in terms of cost. Some people assume we're all millionaires because we didn't just up and starve to death, and some people thing my $500 to share an apartment is outrageous. It was outrageous... outrageously good! Roomie and landlord would chatter long in their tongue and I'd just smile, and wait to pay my half of the reduced rate. Booyah.