Question 339019
Paula mixed 2 cups of sunflower seeds 
3 cups of raisins 
mixture  2900 Calories energy.  
raisins is 400 less than the number of Calories per cup of sunflower seeds.
let calories/cup in sunflower be x
calories /cup in raisins  be y
..
x-y=400.......................1
..
2x+3y=2900....................2
multiply equation 1 by 3 and add to equation 2
3x-3y=1200
2x+3y=2900
ADD
5x=4100
divide by x
x= 4100/5
x=820 calories /cup in sun flower.
raisins contain 400 less. 820-400 = 420 calories