$($Miles Per Gallon$)$ 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 sentinel$-$controlled$-$repetition script

that prompts the user to input the miles driven and gallons used for each tankful$.$ The

script should calculate and display the miles per gallon obtained for each tankful$.$ After

processing all input information, the script should calculate and display the combined

miles per gallon obtained for all tankfuls $($that is$,$ total miles driven divided by total

gallons used$).(4$ points$)$

Enter the gallons used $(-1$ to end$)$: $12\mathrm{.}8$

Enter the miles driven: $287$

The miles$/$gallon for this tank was $22\mathrm{.}421875$

Enter the gallons used $(-1$ to end$)$: $10\mathrm{.}3$

Enter the miles driven: $200$

The miles$/$gallon for this tank was $19\mathrm{.}417475$

Enter the gallons used $(-1$ to end$)$: $5$

Enter the miles driven: $120$

The miles$/$gallon for this tank was $24\mathrm{.}000000$

Enter the gallons used $(-1$ to end$)$: $-1$

The overall average miles$/$gallon was $21\mathrm{.}601423$