let's say that C is "x" units farther from B, that means that CB = x, and therefore AC = 1.5x.
[tex]\bf \underset{\leftarrow ~~30~~\to}{\boxed{A}\stackrel{1.5x}{\rule[0.35em]{18em}{0.25pt}}C\stackrel{x}{\rule[0.35em]{10em}{0.25pt}}\boxed{B}} \\\\\\ AB=AC+CB\implies \stackrel{AB}{30}=\stackrel{AC}{1.5x}+\stackrel{CB}{x}\implies 30=2.5x \\\\\\ \cfrac{30}{2.5}=x\implies 12=x \\\\[-0.35em] ~\dotfill\\\\ AC=1.5(12)\implies AC=18~\hspace{8em} CB=x\implies CB=12[/tex]
