#include <iostream>
#include <cstdio>
#include <cmath>

using namespace std;

double A[1000000], B[1000000];

int N;
double K;

double cal(double h)
{
    double v = 0; K = 0;

    for(int Ni = 0; Ni < N; Ni++)
    {
        double p = max(0.0, A[Ni]-h);
        double t = B[Ni]*p/A[Ni];
        v += t*t*p/3;
        K += t*t;
    }

    return v;
}

int main()
{
    int T;
    scanf("%d", &T);

    while( T-- )
    {
        scanf("%d", &N);

        double H = 0;

        for(int Ni = 0; Ni < N; Ni++)
            scanf("%lf", &A[Ni]), H = max(H, A[Ni]);

        for(int Ni = 0; Ni < N; Ni++)
            scanf("%lf", &B[Ni]);

        double V = cal(0);

        double l = 0, r = H;

        for(int i = 0; i < 30; i++)
        {
            double mid = (l+r)/2;
            if( cal(mid)*2 > V ) l = mid;
            else r = mid;
        }

        printf("%.0f\n", floor(l) );
    }
}