Answer:
Mid grade gas per gallon = $2.67
Regular gas per gallon = $2.37
Step-by-step explanation:
Let, x= mid grade gas, y=regular gas.
So, for 18 gallons of mid grade gas and 5 gallon of regular gas at $59.91, it can be expressed as,
------------------(equation 1)
for 14 gallon of mid grade gas and 1 gallon of regular gas at 39.75, it can be expressed as,
-------------------(equation 2)
-------------------(equation 3)
Now substituting the value of y from (equation 3) in (equation 1) we get,






-------------------------(equation 4)
Now substituting value of x from (equation 4) in (equation 3) we get,




Therefore price per gallon of mid grade gas is x = $2.67, and price per gallon of regular gas y = $2.37.