A typical serving of pasta is 2 ounces of pasta and 1/4 cup of sauce. However, most Americans consume more than the standard size. I would double it to 4 ounces of pasta and 1/2 of sauce per serving. Therefore, I'd use 25 cups of sauce to feed 50 people, however, you may want to add another 5 cups just to be on the safe side.
I'd go with about 8-10 cups of onion per 48oz batch
That is a subjective answer, so in my opinion, I normally serve 2 cups of sauce per pound of pasta. or 30 cups (2 #10 cans, or just less than 2 gallons) for 15 lbs of pasta. Some use more sauce, some use less.
2 cups of cooked pasta is usually between 200 to 400 calories, depending on what kind of pasta(whole grain pasta 200) and a cup of spaghetti tomato sauce is around 330 calories which also varies.
I can of 28 oz. tomatoes will usually get you through a pound of pasta. Sometimes you will have a little leftover.
Make sure your pasta sauce is thick and the pasta is well drained. A good restaurant trick is to put several ladles of sauce into a large skillet and add just enough pasta for two people at a time. Heat sauce and pasta together shaking pan well to thoroughly coat the pasta.
9 cups
In my opinion, if your serving along side other food, you should assume 1 serving per person. One serving of pasta is generally 1/4 a cup of dry pasta. Therefore you should cook 17.5 cups of dry pasta, for your pasta salad.
Somewhere between 100 and 125 cups in 60 lbs of sauce
What that means is 3 cups of pasta measured after you have boiled it. It does NOT mean to measure it out THEN cook it.
There are about 4 cups of uncooked rotini pasta in 16 ounces.
The conversion rate for uncooked pasta to cups can vary depending on the shape and size of the pasta. On average, 500 grams of uncooked pasta is roughly equivalent to about 4 cups of uncooked pasta. It's important to note that this is an approximate conversion, and the exact measurement may vary slightly.