1.5 to 2 cups, depending on the rice
That depends on how long you cook them for. If you cook macaroni to a standard al dente, then you will need 8 cups of dried macaroni noodles; if you over cook them they will swell to 3 or 4 times the dried size, therefore you would only need about 4 cups.
It is really going to depend on the recipe and how thick you want your broth to be. One recipe for a chicken and sausage gumbo I've seen by Paula Dean, you would need 12.5 cups of oil (after browning the chicken) an additional 6.25 cups of butter and 25 cups flour to make the roux for gumbo to serve 50 people.
You need a large pot that has heated walls to cook the rice evenly. Otherwise, you will have unevenly cooked rice.
In the usual cooking method, you would add twice as much water as rice. So 1000 ml, or a liter.
you need 7 cups
Why add salt at all? There is no reason to add salt to rice.
Broth contains basic nutrients required for the propagation of the bacteria
16 cups a day for 30 days would be 480 cups.
6-8 cups
100 cups of soil
You need to prepare every dish for one child and then multiply it by 30 to determine how much you need. Your question can't be answered as it's written since it really depends on what you serve; you wouldn't calculate how many cups of meat you need...you wouldn't calculate how many peas you'd cook but you would calculate how many eggs you need. Just make what you would normally cook for one and then do the math.
John Need-ham heated broth in sealed flasks in 1745