Áp dụng tính chất của dãy tỉ số bằng nhau :
\(\dfrac{x}{3}=\dfrac{y}{4}=\dfrac{z}{5}=\dfrac{x+y+z}{3+4+5}=\dfrac{27}{12}=2,25\)
\(+)\)\(\dfrac{x}{3}=2,25\Rightarrow x=2,25.3=6,75\)
\(+)\)\(\dfrac{y}{4}=2,25\Rightarrow y=2,25.4=9\)
\(+)\)\(\dfrac{z}{5}=2,25\Rightarrow z=2,25.5=11,25\)
Vậy \(x=6,75;y=9;z=11,25\)
\(\dfrac{x}{3}=\dfrac{y}{4}=\dfrac{z}{5}\) và \(x+y+z=27\)
\(\Rightarrow\dfrac{x+y+z}{3+4+5}=\dfrac{27}{12}=\dfrac{9}{4}\)
\(\Rightarrow x=\dfrac{9}{4}.3=\dfrac{27}{4}\)
\(\Rightarrow y=\dfrac{9}{4}.4=9\)
\(\Rightarrow z=\dfrac{9}{4}.5=\dfrac{45}{4}\)
Vậy \(x=\dfrac{27}{4};y=9;z=\dfrac{45}{4}\)
