Question

x/y=7/20 ; y/z=5/8 và x+y+z=118

 

Answer 1

\(\dfrac{x}{y}=\dfrac{7}{20}\Rightarrow\dfrac{x}{7}=\dfrac{y}{20};\dfrac{y}{z}=\dfrac{5}{8}\Rightarrow\dfrac{y}{5}=\dfrac{z}{8}\Rightarrow\dfrac{y}{20}=\dfrac{z}{32}\\ \Rightarrow\dfrac{x}{7}=\dfrac{y}{20}=\dfrac{z}{32}\)

Áp dụng t/c dtsbn:

\(\dfrac{x}{7}=\dfrac{y}{20}=\dfrac{z}{32}=\dfrac{x+y+z}{7+20+32}=\dfrac{118}{59}=2\\ \Rightarrow\left\{{}\begin{matrix}x=14\\y=40\\z=64\end{matrix}\right.\)