Beth wants to go on a road trip this summer. She will be taking her car, which gets an average of 19 miles per gallon in fuel economy. Beth creates an expression to calculate the total cost of gas for her trip, 1/19xy, where x is the typical price of gas (in dollars per gallon) where she will be driving. What does the factor y represent? The number of miles she expects to drive. The total cost of gas, for one fill-up. The number of times she expects she will have to stop to fill up her car with gas. The total amount of gas, in gallons, needed to fill her car's gas tank.