[tex] \frac{x}{ \frac{1}{2} }= \frac{y}{ \frac{1}{5} } = \frac{z}{ \frac{1}{6} } = \frac{x+y+z}{ \frac{1}{2}+ \frac{1}{5}+ \frac{1}{6} }= \frac{520}{ \frac{26}{30} } = \frac{520*30}{26}=600 [/tex], Deci: 2x=600,⇒x=300, 5y=600, ⇒y=120, si 6z=600, ⇒ z=100 .