(120×12.5%×300-300×8%×120)/(300×8%-120×12.5%)
=(4500-2880)/(24-15)
=1620/9
=180克
还可以用方程:
300*8%/(300+x)=120*12.5%/(120+x)
解出x=180
(120×12.5%×300-300×8%×120)/(300×8%-120×12.5%)
=(4500-2880)/(24-15)
=1620/9
=180克
还可以用方程:
300*8%/(300+x)=120*12.5%/(120+x)
解出x=180