[lnพwsะบุ๑sสุ๑xล่o]

$\frac{1}{x} log8=\frac{1}{y} log27=\frac{1}{z} log36$

$x=\frac{log8}{log36} z$

$y=\frac{log27}{log36} z$

$\frac{x+y}{z}=\frac{\frac{log8}{log36} z+\frac{log27}{log36} z}{z}$

$=\frac{log8}{log36} +\frac{log27}{log36} $

$=\frac{log216}{log36}$

$=\frac{3log6}{2log6}$

$=1.5$