Convert your running time to seconds, then do the calculations.
Code:
#include <iostream>
using namespace std;
struct TimeType
{
int min;
int sec;
};
int main(void)
{
int miles;
TimeType running_time;
TimeType time_per_mile;
int mile_time_in_sec, time_in_sec;
cout << "How many miles?";
cin >> miles;
cout << "Enter your time in minutes and seconds";
cin >> running_time.min >> running_time.sec;
time_in_sec = running_time.min * 60 + running_time.sec;
mile_time_in_sec = time_in_sec / miles;
time_per_mile.min = mile_time_in_sec / 60;
time_per_mile.sec = mile_time_in_sec % 60;
cout << "running time:" << running_time.min << " minutes " <<
running_time.sec << " seconds." << endl;
cout << "time per mile:" << time_per_mile.min << " minutes " <<
time_per_mile.sec << " seconds." << endl;
return 0;
}