$\dfrac{2x}{3}=\dfrac{3y}{4}=\dfrac{4z}{5}$
$\Rightarrow\dfrac{12x}{18}=\dfrac{12y}{16}=\dfrac{12z}{15}$
Áp dụng tính chất dãy tỷ số bằng nhau, ta có :
$\Rightarrow\dfrac{12x}{18}=\dfrac{12y}{16}=\dfrac{12z}{15}=\dfrac{12x+12y+12z}{18+16+15}$
$=\dfrac{12(x+y+z)}{49}=\dfrac{12.49}{49}=12$
Do đó :
$\dfrac{2x}{3}=12\Rightarrow2x=36\Rightarrow=18$
$\dfrac{3y}{4}=12\Rightarrow3y=48\Rightarrow=16$
$\dfrac{4z}{5}=12\Rightarrow 4z=60\Rightarrow=15$
