1,设井深xm,则2(x+3.5)=3(x+0.6),解得x=5.2 绳长是2×(5.2+3.5)=17.4 ,
2,设母鸡x,小鸡y,则,4x+1/4y=47,和,x+y=68,得,x=8,y=60
3,设甲x,乙y,则,1/3x+1/5y+48=(1-1/3)x=(1-1/5)y,得,x=200,y=240
小学几年级的奥数啊.
1,设井深xm,则2(x+3.5)=3(x+0.6),解得x=5.2 绳长是2×(5.2+3.5)=17.4 ,
2,设母鸡x,小鸡y,则,4x+1/4y=47,和,x+y=68,得,x=8,y=60
3,设甲x,乙y,则,1/3x+1/5y+48=(1-1/3)x=(1-1/5)y,得,x=200,y=240
小学几年级的奥数啊.