x/2400X40%/1-x/2400X40%=8%x/2400X2/5X2400/(1-x)X2/5=2/252X2400X2x÷〔2400X5(1-x)X5〕=2/254x=2/25〔5(1-x)X5〕4x=2/25X5(1-x)X54x=2X5(1-x)X5/254x=2(1-x)4x=2-2x2x=1-x3x=1x=1/3