x比y等于3比4,30+x比50+y等于5比7,求x和y

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x比y等于3比4,30+x比50+y等于5比7,求x和y
x比y等于3比4,30+x比50+y等于5比7,求x和y

x比y等于3比4,30+x比50+y等于5比7,求x和y
由题得,4x=3y ①
3×(30+x)/3×(50+y)=(90+3x)/(150+3y)=5/7②
①代入②中得
(90+3x)/(150+4x)=5/7
解得x=120
∴y=160

x/y=3/4
(30+x)/(50+y)=5/7,推出:25+5y=210+7x
推出x=4y/3,代入得:25+5y=210+28y/3,得出y=583/3,再代入x=4y/3,
得x=2332/9