How much ground beef do you need to make 40 decent-sized hamburgers for grilling?
Keep in mind that burger patties in restaurants come in four typical sizes, 1/4, 1/3, 1/2, & 3/4 pound patties. The average person can be expected to eat the 1/2 pound patty at a typical barbecue. Multiply 40 by 1/2 and you get 20 pounds. Keep in mind, the leaner the meat, the less the shrinkage, but greater leanness means less fat, and less taste (unless you add some). Give me an Angus bacon and cheese with no onions, pickles, tomatoes, Just leave lettuce, bacon, patty, and buns.