You cannot directly convert volumes to weight. Your question has no answer as posted.
12 kilo of water is 52.8 cups.
A kilo of chopped rhubarb is approximately 6 cups.
approximately 4.409 cups of water in 1 kilo.
4.409 cups in a kilo, so 1/3 is approximately 1.469 cups.
There are 5 cups in a kilo of sugar.
A "cup" equates to 200grams. There are 1000 grames in one Kilo therefore 1000/200 = 5 (cups)
That is 2.205 cups.
That is approximately 4.409 cups
About 4.2 cups.
That is about 8 cups
4.? cups
That is approximately 3.3 cups