Answer
$26\;mi/gal$.
Work Step by Step
Distance $d=620\;mi$.
Fuel $f=24.2\;gal$.
Miles per gallon $=\frac{d}{f}$.
Substitute all the values.
$=\frac{620\;mi}{24.2\;gal}$
Simplify.
$=25.6198347107\;mi/gal$
Rounded value.
$=26\;mi/gal$.