Answer:
Fantasia's family's car is more fuel-efficient.
Step-by-step explanation:
Given that, Tiyleah's family's car is getting 40 miles per gallon, and Fantasia's family's car uses 7 liters per 150 km.
The comparison can be done by observing the distance traveled by the cars in an equal amount of fuel. The car which covers more distance in an equal amount of fuel is more fuel-efficient.
First, convert the given units to have the same unit of measurement,
As 1 gallon =3.7854 liters and 1 mile = 1.609344 km
So, 40 miles =40 x 1.61=64.40 km
Now, The distance covered by Tiyleah's family's car is 64.40 km in 3.7854 liters.
So, the distance covered by Tiyleah's family's car in 1 liter of fuel is km
In a similar way,
As Fantasia's family's car uses 7 liters per 150 km.
So, the distance traveled by Fantasia's family's car in 1 liter of fuel =150/7=21.43 km
Observe that, in 1 liter of fuel, Tyleah's family's car covered 17.01 km while Fantasia's family's car covered 21.43 km which is more.
Hence, Fantasia's family's car is more fuel-efficient.
