x/30 -x/40 =1+ 24/100左边通分,合并,右边化简=>10x/1200 =31/25=>化简25x = 31*120=>x=31*120/25=148.8
x/30-x/40=1.24x/12=1.24的x=31/30
x/30-x/40=1+6/25
