0.5x+0.3(100-x)=420
问题描述:
0.5x+0.3(100-x)=420
答
0.5x+30-0.3x=420
0.2x=390
x=1950
0.5x+0.3(100-x)=420
0.5x+30-0.3x=420
0.2x=390
x=1950