how many 4' subs for about 50 people?!
Measure about a 4" sandwich per person and a half a cup of the salads.
I am a Chef,caterer.
I would do at least one per person and then a couple extra. Now, if you have a lot of guys, then I would do a lot extra - men usually have bigger appetites so you'll need more sandwiches, but if it's mostly women, 1 per person and a few extra.
5-6 inches a person that is 5 or 6, 4 foot subs. Good Luck
Twenty Five Subs will do it!!