Bonsoir;
300km -> 9 galons
100km -> 9/3 => 3gallons
5000km -> 3*5 => 15 gallons
150 km -> 100+100/2 -> 3+3/2 = 4,5gallons
9 gallons -> 300km
1 gallon -> 300/9 =>33,33km
6 gallons -> 33,33*6 => 200km
2 gallons -> 33,33*2 => 66,66km
18 gallons ->3,33*18 => 600km