posted by john .
Paula mixed 2 cups of sunflower seeds and 3 cups of raisins yo make a snack for a hike. She figured that the mixture would provide her with 2900 calories of food energy. Finf the number of calories per cup of raisins if it is 400 less than the number of calories per cup of sunflower seeds. I came up with 820 per cup sunflower and 420 per cup raisins but how would I write the equation?