How many pounds of sliced roast beef will be needed to serve 60 sandwiches?

I need more information to answer this question! Here's why:

* How much roast beef per sandwich? Are you making small, single-slice sandwiches or larger, multi-slice sandwiches?

* What kind of roast beef? Some cuts are more efficient for sandwiches than others.

Once you tell me how much roast beef you'll use per sandwich, I can calculate the total amount you'll need!