$x:y:z=\frac{2}{3}:\frac{3}{5}:\frac{3}{4}$
$\Rightarrow \frac{x}{\frac{2}{3}}=\frac{y}{\frac{3}{5}}=\frac{z}{\frac{3}{4}}$
Áp dụng tính chất dãy tỉ số bằng nhau ta có:
$\Rightarrow \frac{x}{\frac{2}{3}}=\frac{y}{\frac{3}{5}}=\frac{z}{\frac{3}{4}}=\frac{x-y+z}{\frac{2}{3}-\frac{3}{5}+\frac{3}{4}}=\frac{49}{\frac{49}{60}}=49.\frac{60}{49}=60$
$\frac{x}{\frac{2}{3}}=60\Rightarrow x=60.\frac{2}{3}=40$
$\frac{y}{\frac{3}{5}}=60\Rightarrow y=60.\frac{3}{5}=36$
$\frac{z}{\frac{3}{4}}=60\Rightarrow z=60.\frac{3}{4}=45$
