75 grams per person, so 7.5 kilos plus sauce
About 5-6 cups per pound
At 100 grams per person, 70,000 grams
Normally You should make 2oz per person. This number can lower if you are making Chickenparm. Or the amount could be higher if making a light sauce.
Figure 8 servings per dry pound of spaghetti. For 35 servings, then, you'd need 8 servings x N pounds = for 35 people N = 4.375 lbs. of spaghetti So you need to buy 5 pounds of spaghetti to serve 35 people. Personally, I don't think 8 servings per pound is enough for each person. I like spaghetti too much. I would personally figure 5 servings per pound. That would mean: 5 servings x N pounds = for 35 people N = 7 lbs. of spaghetti. But maybe I'm too much of a piggy about it!
It isn't really possible to say precisely how much sauce per 1lb pasta because it depends on the type of sauce. A plain, rich, smooth tomato sauce should just coat the pasta; the pasta mustn't be swimming in it. You might allow more per serve if the sauce is chunky or thick. To get a rough idea, 1lb pasta (a bit under 500g) serves four to five people, so to be on the safe side pick any sauce recipe designed to serve six people; leftover sauce can be refrigerated and later added to stews or casseroles, or served on toast.
If you work on 120g per person per serve you should need approximately 2400g which is 2.4 kilos. Depending on what other ingredients you are adding (i.e. onion, carrot, celery) to round off the measure and to allow for any shrinkage use 2.5kilos.
If you plan for 6 oz per person, that would be 300X6=1800 oz / 16 = 112.5 pounds.
Sixteen, same as a pound of anything but gold or silver and with those they use troy ounces, twelve in a pound.
Plan on three to four ounces of uncooked spaghetti per person. For 150 people, this is 28-38 lbs uncooked pasta. Adjust based upon nature of your guests and other meal choices. If you are feeding the football squad and have few side dishes then you may need twice as much. If you are feeding a couple busloads of 2nd graders on a field trip and have other dishes available then you could probably do half as much. For reference, the Armed Forces Recipe guide for spaghetti w/meat sauce calls for 12 lbs of uncooked pasta to serve 100 portions of 1 cup each. That's about two ounces per person--and I can tell you from experience that it is not enough. https://nll1.ahf.nmci.navy.mil/recipe/
About 13 jars. For American Italian dining, figure 4 ounces of sauce per person (assuming you are doing spaghetti) 4 x 200= 800, divided by 64 is 12.5 Don't forget the grated cheese.
The general rule of thumb is that one pound feed 5-6 people. So go general, one pound feeds five, ten pounds should feed fifty. Think about it though, if you are considering feed spagetti to say a group of football players at perhaps a pregame dinner, it is better to think more (much more) than less. I would, from personal experience, double the amount you would cook for the average group.