How much does a person have to drink to be drunk?

Depends on their tolerance and other factors.

With approximately 4 drinks you will be legally drunk according to your blood alcohol content. How much the alcohol affects after each drink depends on a lot of factors though. After just 2 drinks measurable impairment is observed in most people.

You'll feel it after one beer.

I'm concerned that you have made a big deal out of it. If you (or anyone else) drinks one drink a year but thinks of the drink all year long, he or she is an alcoholic.

I did, um, research in this field for 13 years before I went to AA and sobered up.

You don't want to take the chance that it'll grab hold of you.

Alcohol gave me wings to fly,
And then took away the sky.

Be careful, be very careful.

Ted

That depends completely on the person, his health, his fitness and his drinking habits: no universal rule is possible as speed of absrobtion differs widely (as does speed of alcohol decay in the body)
In some European countries , drunken driving starts at 0.5 promille (long ago it was 1.5, then reduced to 0.8, now to 0.5 promillle= less than 3 glasses of wine) I don't know the law in the USA.

European beers come with widely different alcohol contents, the stongest containing as much alcohol as Martini. (from 2% to 16% I think)

A liter of 4,7% proof should be plenty to get your buzz on without any danger of passing out.

It depends on many different factors weather the person is a guy or a girl, how much he or she weights if he or she drinks often among other factors as well.