#include<iostream>
using namespace std;
int main()
{
    double miles,gallon,MPG,total=0,avg=0,avg1=0,count=0;


    while(miles>=-1)
    {
        cout<<"Enter miles driven(-1 to quit):"<<endl;
        cin>>miles;
        if(miles==-1)
            break;
        else
         cout<<"Enter gallons used:"<<endl;
        cin>>gallon;


            MPG=miles/gallon;
            avg+=miles;
            avg1+=gallon;

            cout<<"MPG this tankfull:"<<MPG<<endl;
            total=avg/avg1;

            cout<<"total MPG:"<<total<<endl;
        }


    return 0;


}