[X(1+40%)••90%+ X(1+40%)•10%•70%]-(X+300)= [X(1+40%)-(X+300)]•85%
1.26X+0.098X-X-300=(1.4X-X-300)•0.85
0.358X-300=0.34X-255
0.018X=45
X=2500
[X(1+40%)••90%+ X(1+40%)•10%•70%]-(X+300)= [X(1+40%)-(X+300)]•85%
1.26X+0.098X-X-300=(1.4X-X-300)•0.85
0.358X-300=0.34X-255
0.018X=45
X=2500