I am having a party for 150 average to heavy drinkers. How many beers/kegs and liquor should I buy?

kegs come in 15.5 gals. and 2 kegs should be enough they also sell 5 to 7 gals. if you want to get different kinds of beer. depending on what everybody drinks, standard is rum, vodka, tequila, scotch or boubon, vermouth,olives(green), orange juice,coke, sprite, tonic water and soda water. you want to get fancy? sour mix for marguerita and mint leaves with sugar for mint julep ( with scotch or bourbon is best) as always drink responsibly. ask people to deposit car keys first and quick dial cab numbers for peace of mind.