Question

x(1+50℅)×90℅+(500-x)×(1+40℅)×90℅-500=148.x的解是多少？

Answer 1

x(1+50℅)×90℅+(500-x)×(1+40℅)×90℅-500=148.
x(1+50/100)×90/100+(500-x)×(1+40/100)×90/100-500=148.
x(1+0.5)×0.9+(500-x)×(1+0.4)×0.9=148.+500
(1.5x)×0.9+(500-x)×1.4×0.9=648.
[(1.5x)+(500-x)×1.4]×0.9=648.
[1.5x+(500-x)×1.4]=648/0.9.
[1.5x+500x1.4-1.4x]=720
0.1x+700=720
x=200

Answer 2

解：原题为：
x（1+50%）90%+（500-x）（1+40%）90%-500=148

x（150%）90%+（500-x）140%90%=148+500=648

150%x+（500-x）140%=64890%=720

150%x+500140%-x140%=720

10%x=720-500140%=20

x=20/10%=200。