How many pounds of salad or lettuce to feed 200 people?

1st- Get an estimate of how much people are eating ( I would that the average person would not eat more than maybe less than less than 1/4 of a head of lettuce.)

2nd- After you guess (or estimate) how much each person will eat, find the average (add all of the numbers up and then divide by how many numbers there are)

3rd- multiply that answer by 125 (the whole number will be how many heads of lettuce you need then the fraction (if any) will be out of a whole head of lettuce (i would simplify that)

4th- if there is a fraction then i would round it to the nearest whole number (I would round up to make sure that there is enough food for everybody.