Question

Tìm x, y biết :

x/3 = 1/5 và x + y = 72

😊

Answer 1

x/3=y/5 => x+y/3+5=72/8=9

+,x/3=9=>x=27

+,y/5=9=>y=45

Answer 2

\(\frac{x}{3}=\frac{y}{5}\Rightarrow\frac{x}{3}:\frac{y}{5}=1\Rightarrow\frac{x}{3}.\frac{5}{y}=1\Rightarrow\frac{x}{y}=\frac{3}{5}\)

mà \(x+y=72\)

vậy +) \(x=\frac{3}{5+3}-72\)

             \(=\frac{3}{8}-72\)

             \(=27\)

        +) \(y=72-27\)

              \(=45\) 

thank trc  ^__^