A large head of lettuce should be enough to feed up to 6 people, depending on what else you are adding to it. For 30 people, about five heads of lettuce should suffice.
If you have other ingredients, then 1/2 cup per person should do. I usually add a few cups extra so that people can have seconds. With dressing on the side, it is easily saved as a leftover.
You would need 3 average lettuce.
One large head should do nicely especially if complemented with other things like cucumbers, tomatoes, celery, etc.
About 2 lettuce leafs and 2-3 slices of cucumber - that is a pretty small salad.
That is 87.5 pounds
This depends upon portion size, the type of lettuce you and how many other ingredients are in the salad. Generally you decide on a recipe and, according to how many portions it will serve, multiply the amount of lettuce per portion by 70.
It depends on the size and if you're talking about a large dinner salad or petite side salad. A typical head of iceburg lettuce can easily be split into fours for a side cobb salad. However, for an entree, you might only get two servings out of a medium head.
You need 12 lbs of mixed lettuce and about 1 gallon of dressing(more if creamy).
if for 1 hamburger you need 2 the you will need twice as many lettuce them hamburgers so that will be 1,000 lettuce leathers
Toss your salad with just enough Caesar dressing to coat the leaves; too much dressing will make your lettuce or other greens lose their crispness too soon and go limp.
if that is the only thing they are eating figure 12-16oz, if that is only as an appetizer figure 6-8 oz. So 150 pounds for an entree and 75-100 pounds for an appetizer
This would depend on what is in the salad, if you are going to prepare it and then refrigerate it, and if you leave the dressing off until you serve it. If the salad has cucumbers, tomatoes, or other vegetables that contain a lot of natural moisture, it can cause your lettuce to become limp. If you make the salad(s) then refrigerate, it will remain crisp and brightly colored. If you combine your dressing with the salad too far in advance, it will cause the lettuce to become limp, as well. Ideally, if all of these guidelines are followed, you can make it about a day ahead of time. Also, if you are cutting your own lettuce up, and aren't eating the salad immediately, you should TEAR the leaves, and NOT use a knife. The reaction with the knife and lettuce is what causes the brown edges on the leaves.
I would make 125 pounds of salad.