Answer:
Miles he drove on highway = 180 miles
Miles he drove in the city = 217 miles
Step-by-step explanation:
Lets assume that gallon used on highway = x
Miles driven on highway = y
(I) 36 miles per gallon on the highway.
36x = y equation 1
(II) 31 miles per gallon in the city.He recently drove 397 miles on 12 gallons of gasoline
31(12-x)= 397-y equation 2
372-31x= 397-y
Combine the constants:
-31x= 397-372-y
y-31x = 25
Now substitute the value of equation 1 in equation 2
y-31x=25
36x-31x=25
5x=25
Now divide both sides by 5
5x/5=25/5
x=5
Now substitute the value x=5 in equation 1
36x=y
36(5)=y
180= y
Now subtract the miles driven on highway from recently drove miles to get the miles driven in the city.
397-y = 389 - 180
= 217
Therefore,
Miles he drove on highway = 180 miles
Miles he drove in the city = 217 miles ....