Answer
A driver could save a time of $~~1.2~hours$
Work Step by Step
We can convert the distance $700~km$ to units of miles:
$(700~km)\times (\frac{1~mi}{1.609~km}) = 435~mi$
We can find the time to drive this distance at a speed of $55~mi/h$:
$t = \frac{d}{v} = \frac{435~mi}{55~mi/h} = 7.9~h$
We can find the time to drive this distance at a speed of $65~mi/h$:
$t = \frac{d}{v} = \frac{435~mi}{65~mi/h} = 6.7~h$
We can find the difference in the required time:
$\Delta t = 7.9~h-6.7~h = 1.2~h$
A driver could save a time of $~~1.2~hours$
