At a corner gas station, the revenue R varies directly with the number g of gallons of gasoline sold. If the revenue is $38.25 when the number of gallons sold is 9, find a linear equation that relates revenue R to the number g of gallons of gasoline. Then find the revenue R when the number of gallons of gasoline sold is 12.5.
Write the linear equation that relates R to g

R=(Simplify your answer.)