Math Exam with time in C++

#include <iostream>
#include <windows.h>
#include <time.h>
#include <conio.h>
using namespace std;
int main()
{
int j=0;
    for (int a=3; a>0 ; a--)
    {
        cout<<"\rGet ready to play in : "<<a;
        Beep(2000,300);Beep(0,700);
    }
    Beep(0,500);
        cout << "\n( YOU HAVE ONLY 5 SECONDS TO SOLVE EACH QUESTION )\n-----------------------------------------------------------------------\n\n";
        Beep(0,4000);
        for ( int i=1; i<=5; i++)
        {
            srand(time(0));
            int A = rand()%10+1+10*(i-1);
            int B = rand()%10+1+10*(i-1);
            cout << " Question " << i << " :     " << A << " + " << B << " = ";
            int numInput;
            time_t start = time(0);
            while ( !kbhit() )
            {
                if (abs(time(0) - start) > 5)
                {
                    j=1;
                    break;
                }
            }
            if (j==1)
            {
                cout << " Time's Up!!";
                j=2;
            }
             else
            {
                cin >> numInput;
                if ((time(0)-start)>5)
                {
                    cout << " Time's Up!!";
                    j=2;
                }
                else if ( numInput == A+B ) cout << " Good Job!!\n\n";
                else
                {
                    cout << " Wrong Answer!!";
                    j=2;
                }
            }
            if (j==2) break;
        }
}