Question

A car gets miles/gallon on the highway and 20 miles/gallon in the city. estimate the average miles/gallon for a trip consisting of 60 miles on the highway and 10 miles in the city, then convert this number to SI umits (km/L).

Answer 1

Mileage in highway is missing, for example i am considering 40 miles/gallon

Given

1 gallon =40 miles (on highway)

1 gallon =20 miles (in city)

In Highway

For

1 gallon--40 miles

X gallons --60 miles

=>X =60*1/40 =1.5 gallons

In City

For 1 gallon--20 miles

Y gallons -10 miles

Y=10*1/20 =0.5 gallons

Therefore

Average mileage( miles/gallon) =Total miles /Total Gallons =(60+10)/(1.5+0.5) =35 miles/gallon

in Km/L

1 miles/gallon =0.425144 km/L

Therefore

Average mileage (Km/L) =35*0.425144=14.88 km/L