#include <iostream>

 #include <cstdio>

 #include <cstring>

 #include <cstdlib>

 #include <algorithm>

 #include <queue>

 #include <vector>

 #include <map>

 #include <string>

 #include <cmath>

 #define min(a, b) ((a) < (b) ? (a) : (b))

 #define max(a, b) ((a) > (b) ? (a) : (b))

 #define abs(a) ((a) < 0 ? (-1 * (a)) : (a))

 template<class T>

 inline void swap(T &a, T &b)

 {

     T tmp = a;a = b;b = tmp;

 }

 inline void read(int &x)

 {

     x = ;char ch = getchar(), c = ch;

     while(ch < '' || ch > '') c = ch, ch = getchar();

     while(ch <= '' && ch >= '') x = x *  + ch - '', ch = getchar();

     if(c == '-') x = -x;

 }

 const int INF = 0x3f3f3f3f;

 const int MAXN =  + ;

 const int MAXM =  + ;

 int x[MAXM], y[MAXM], node[MAXM], n, m, t, u[MAXM], v[MAXM], cnt[MAXM], fa[MAXM], vis[MAXN];

 double ma[MAXN][MAXN], w[MAXM];

 struct Edge

 {

     int u,v,nxt;

     double w;

     Edge(int _u, int _v, double _w, int _nxt){u = _u;v = _v;w = _w;nxt = _nxt;}

     Edge(){}

 }edge[MAXM << ];

 int head[MAXN], cntt;

 inline void insert(int a, int b, double c)

 {

     edge[++cntt] = Edge(a,b,c,head[a]);

     head[a] = cntt;

 }

 int find(int x){return x == fa[x] ? x : fa[x] = find(fa[x]);}

 int cmp(int x, int y){return w[x] < w[y];}

 int tiaoshi;

 void dfs(int x, int pre)

 {

     vis[x] = ;

     for(int pos = head[x];pos;pos = edge[pos].nxt)

     {

         int v = edge[pos].v;

         if(v == pre) continue;

         for(int i = ;i <= n;++ i)

             if(i == v || !vis[i]) continue;

             else ma[i][v] =ma[v][i] = max(ma[i][v], max(ma[v][i], max(ma[x][i], max(ma[i][x], edge[pos].w))));

         dfs(v, x);

     }

 }

 int main()

 {

     read(t);

     for(;t;--t)

     {

         tiaoshi = ;

         read(n);memset(ma, , sizeof(ma)), memset(vis, , sizeof(vis)), memset(head, , sizeof(head)), cntt = , m = ;

         for(int i = ;i <= n;++ i) read(x[i]), read(y[i]), read(node[i]);

         for(int i = ;i <= n;++ i)

             for(int j = i + ;j <= n;++ j)

                 ++ m, u[m] = i, v[m] = j, w[m] = sqrt((x[i] - x[j]) * (x[i] - x[j]) + (y[i] - y[j]) * (y[i] - y[j])), cnt[m] = m, fa[m] = m;

         std::sort(cnt + , cnt +  + m, cmp);

         int tmp = ;

         double ans = ;

         double ans2 = ;

         for(int i = ;i <= m;++ i)

         {

             int f1 = find(u[cnt[i]]), f2 = find(v[cnt[i]]);

             if(f1 == f2) continue;

             fa[f1] = f2;

             insert(u[cnt[i]], v[cnt[i]], w[cnt[i]]), insert(v[cnt[i]], u[cnt[i]], w[cnt[i]]);

             ans += w[cnt[i]];

             ++ tmp;if(tmp == n - ) break;

         }

         dfs(, -);

         for(int i = ;i <= n;++ i)

             for(int j = i + ;j <= n;++j)

             {

                 if(ans == ma[i][j]) continue;

                 ans2 = max(ans2, (double)(node[i] + node[j]) / (ans - ma[i][j]));

             }

         printf("%.2lf\n", ans2);

     }

     return ;

 }