The fuel economy of a vehicle, in miles per gallon (mi/gal), can be modeled by a quadratic function of the vehicle's speed. A team of engineers is testing a new vehicle for fuel economy and finds that its maximum fuel economy of 30 mi/gal is achieved at a speed of 46 miles per hours (mi/hr). In high speed tests, the fuel economy is found to be 14 mi/gal at a speed of 88 mi/hr. What is the expected fuel economy at a speed of 58mi/hr?