Drivers are concerned with the mileage obtained by their automobiles. One driver has kept track of several tankfuls of gasoline by recording miles driven and gallons used for each tankful. Develop a C++ program that inputs the miles driven and gallons used for each tankful. The program should calculate and display the miles per gallon obtained for each tankful and print the combined miles per gallon obtained for all tankfuls up to this point. The results should look like the following: (Use the five-step problem solving methodolo Enter the miles used (-1 to quit): 287 Enter gallons: 13 MPG this tankful: 22.076923 Total MPG: 22.076923 Enter the miles used (-1 to quit): 200 Enter gallons: 10 MPG this tankful: 20.000000 Total MPG: 21.173913 Enter the miles used (-1 to quit): -1