80%x+(500-X)60%=500*75% 急
问题描述:
80%x+(500-X)60%=500*75% 急
答
80%x+(500-X)60%=500*75%
08X+0.6(500-X)=500*.075
08X+0.6*500-0.6X=375
0.2X+300=375
0.2X=75
X=75/0.2
X=375