A6. When Matej had driven $\frac{5}{6}$ of the way, he had $12 \mathrm{~km}$ left to reach his destination. What is the total length of the journey?
(A) $60 \mathrm{~km}$
(B) $72 \mathrm{~km}$
(C) $48 \mathrm{~km}$
(D) $36 \mathrm{~km}$
(E) $10 \mathrm{~km}$
A6. If we denote the entire distance as $x$, then $\frac{1}{6} x=12 \mathrm{~km}$. The solution to the equation is $x=72 \mathrm{~km}$.