由x/2=y/5 推出x=2y/5.1式
由25%x+40%y=1.4 推出5x+8y=28 2式
将1式代入2式,得,y=2.8 则x=1.12
答：x=1.12,y=2.8
x/2=y/5 25%x+40%y=1.4
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