Encircled in the diagram is the value to be calculated:
So by forming equations from the diagram:
(2/5)X - (2/5)Y = 200
(X-Y) = 200*5/2 = 500
So by forming equations from the diagram:
(2/5)X - (2/5)Y = 200
(X-Y) = 200*5/2 = 500