[tex] \frac{18}{x} = \frac{15}{y} = \frac{47}{z} = k \\ \frac{18}{x} = \frac{k}{1} = = > x = \frac{18}{k} \\ \frac{15}{y} = \frac{k}{1} = = > y = \frac{15}{k} \\ \frac{47}{z} = \frac{k}{1} = = > z = \frac{47}{k} [/tex]
[tex]x + y + z = \frac{18}{k} + \frac{15}{k} + \frac{47}{k} = 40 \\ \frac{18 + 15 + 47}{k} = 40 \\ \frac{80}{k} = 40 \\ k = 80 \div 40 \\ k = 2[/tex]
[tex]x = \frac{18}{2} = 9\\ y = \frac{15}{2} \\ z = \frac{47}{2} [/tex]
