Explanation:
it is the same way as we just handled your question about 3 liters for 61 km.
this car has a petrol (gasoline) usage ratio of
3 liters / 51 km = 3/51 liters/km = 1/17 liters/km
so, 1 liter per 17 km.
so, again, we need to find the factor f to turn 3 into 14. or in our case here possible to turn 1 into 14. depending on whether we use 3/51 or 1/17 as our base.
and then we have to multiply both sides of the ratio by this factor (to keep the overall value of the ratio unchanged). and the "km" side of the ratio will tell us how far the car gets when using 14 liters.
to show you the principle (and that both would do actually the same), I will do it with both :
3/51
3 to 14
3 × f = 14
f = 14/3
3/51 liters/km × f/f = 3/51 × (14/3)/(14/3) =
= (3×14/3)/(51×14/3) = 14/(714/3) =
= 14/238 liters/km
the car will go 238 km when using 14 liters.
and now for 1/17
1 to 14
1 × f = 14
f = 14
1/17 liters/km × f/f = 1/17 × 14/14 = 14/238
again, the car will go 238 km when using 14 liters.