Have vehicles gotten more fuel-efficient over the years? between 1960 and 1999 the size and shape of automobiles in the united states has changed almost annually. the amount of fuel consumed by these vehicles has also changed. the following table describes the average fuel consumption per year per passenger car in gallons of gasoline.

option A. 9.2 gal/year

Justification:

The average rate of change from 1960 to 1970 is the change on the variable  gallons consumed per passenger car divided by the period

average rate of change = Δg / Δt

Δg = 760 gallons - 668 gallons

Δt = 1970 year - 1960 year

                                               760 gal - 668 gal              92 gal    
average rate of change =  = = 9.2 gal / year
                                             1970 year - 1960 year        10 year

9.2 gal / year

As you see for this specific period, 1960 to 1970, the vehicles increased their consumption of gas per passenge, meaning that they became less efficient.