$\dfrac{x}{3}=\dfrac{y}{2}→\dfrac{x}{15}=\dfrac{y}{10}$
$\dfrac{x}{5}=\dfrac{z}{4}→\dfrac{x}{15}=\dfrac{z}{12}$
$→\dfrac{x}{15}=\dfrac{y}{10}=\dfrac{z}{12}$
Áp dụng tính chất dãy tỉ số bằng nhau:
$\dfrac{x}{15}=\dfrac{y}{10}=\dfrac{z}{12}=\dfrac{x+z-y}{15+12-10}=\dfrac{68}{17}=4$
$→\begin{cases}\dfrac{x}{15}=4→x=4.15=60\\\dfrac{y}{10}=4→y=4.10=40\\\dfrac{z}{12}=4→z=4.12=48\end{cases}$
Vậy $(x;y;z)=(60;40;48)$
