algebra
posted by john .
Paula mixed 2 cups of sunflower seeds and 3 cups of raisins to make a snack for a hike. she figured that the mixture would provide her with 2900 calories of food energy. Find 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 an answer of 820 caloies each cup of sunflower and 420 calories each cup of raisins but how would I write the equation?

answer is 420 calories. this is actually a 14 year old.