修一条公路,每天修30米,需要4天修完,如果每天修40米,需要几天修完?2d9y,O*~8],A5h6y8Y
算式:提示+P,T/w'_6g4H2d9y,O*~8],A5h6y8Y
答:需要:?*f8]+C6W9?)[+`-T天修完。2d9y,O*~8],A5h6y8Y