Answer :

the answer would be 24
[tex]1)\ \ \ \frac{18}{27} = \frac{18:9}{27:9} = \frac{2}{3} = \frac{2\cdot 8}{3\cdot 8} = \frac{16}{24}\\\\or\\\\2)\ \ \ 18:27=16:x\ \ \ \Leftrightarrow\ \ \ \frac{18}{27}= \frac{16}{x} \ \ \ \Leftrightarrow\ \ \ 18\cdot x=27\cdot16\ /:18\\\\x= \frac{\big{27\cdot16}}{\big{18}} \ \ \ \Rightarrow\ \ \ x= \frac{\big{9\cdot3\cdot2\cdot8}}{\big{9\cdot2}} \ \ \ \Rightarrow\ \ \ x=3\cdot8 \ \ \ \Rightarrow\ \ \ x=24\\\\\\Ans.\ \ 24[/tex]