we know that
[tex] speed=\frac{distance}{time} [/tex]
Solve for the time
[tex] time=\frac{distance}{speed} [/tex]
in this problem
[tex] speed=55\frac{miles}{hour} \\ \\ distance=310 miles [/tex]
substitute in the formula above
[tex] time=\frac{310}{55} \\ \\ time=5.64\ hours [/tex]
convert to minutes
[tex] 5.64*60=338.4\ minutes =338\ minutes [/tex]
therefore
the answer is
[tex] 338\ minutes [/tex]