ANSWER:
35 miles
STEP-BY-STEP EXPLANATION:
We can make a proportion, since we know the number of miles per 18 gallons, so for 2 3/10 gallons we can calculate the number of miles proportionally
[tex]\begin{gathered} 2\frac{3}{10}=\frac{23}{10} \\ \text{The proportion is} \\ \frac{270}{18}=\frac{x}{\frac{23}{10}}\rightarrow\frac{270}{18}=\frac{10x}{23} \end{gathered}[/tex]solving for x:
[tex]\begin{gathered} 18\cdot10x=270\cdot23 \\ 180x=6210 \\ x=\frac{6210}{180} \\ x=34.5\cong35 \end{gathered}[/tex]Therefore you can travel a total of 35 miles.