Question 1200012
Setup a table of information.
<pre>
Route Part    Rental Rate    Distance     Fuel Efficiency   Fuel Price    Speeds
A to B                       250 miles     10 km/L          $4.25/gal.     120 km/hr
B to C                       175 miles     18 km/L          everywhere     100 km/hr
C to A                       320 miles     24 km/L            " "          140 km/hr
</pre>

I will not tell or explain everything.

(1) Sum the distances.

(2) Convert from dollars per gallon to euros per liter first.

(3)  SPEED*TIME=DISTANCE