1 cut into little pieces
One head of lettuce should feed 8-10 people, so for 50 people factor 5-6 heads of lettuce.
13 pounds
You don't mention whether this is for salad or for sandwiches. For side salads, you would need 12 to 14 medium size heads of lettuce for 100 people.
8 for tomatoes and 4 lettuce heads
a billion
8-10 heads of lettuce depending on how much lettuce you use
28 = (70 / 5) * 2
if it's only lettuce, then 35 heads ish. could be less. depends on the lettuce, what you're making and how hungery the people are.
100... rabbits? kids? zombies?
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.
Yes, this is correct many people called 'space farmers' have to almost fish the lettuce out as when lettuce is in space the lettuce can move at around 30mph.
If it's only a starter salad, I would use about 15 pounds romaine with 5 pounds other green veg.