Question

A car can cover a distance of 357 km on 42 litres of petrol. How far can it travel on 12 litres of petrol?

Answer 1

Distance covered by the car with 42 L of petrol = 357 km
Distance covered by the car with 1 L of petrol = $\frac{357}{42}$ km [less petrol, less distance]
Now, distance covered by the car with 12 L of petrol = $\frac{357}{42}\times 12$ = 102 km [more petrol, more distance]