Just simplify the ratio that you have, and make it so that the side with the liters = 1.
We know g(106) = 28. so g = (28/106)= 14/53.
g(l) = (14/53)l.
When purchasing fuel in Canada, Joe fills his empty gas tank with 106 liters of gasoline. Joe knows his tank holds 28 gallons of gas. Use this information to write an exact function g(l) in terms of liters (l) that would convert liters into gallons.
I can do it where you use a ratio, but my answer isn't very specific or exact, it's also not g(l).