1 /* ***********************************************
  2 MYID    : Chen Fan
  3 LANG    : G++
  4 PROG    : 4081
  5 ************************************************ */
  6 
  7 #include <iostream>
  8 #include <cstdio>
  9 #include <cstring>
 10 #include <algorithm>
 11 #include <queue>
 12 #include <cmath>
 13 #include <bitset>
 14 
 15 using namespace std;
 16 
 17 typedef struct pnod
 18 {
 19     int x,y,p;
 20 } pnode;
 21 pnode p[1010];
 22 
 23 typedef struct nod
 24 {
 25     int a,b;
 26     double c;
 27     friend bool operator < (nod a,nod b)
 28     {
 29         return a.c>b.c;
 30     }
 31 } node;
 32 
 33 node edge[1000010];
 34 int start[1010],num[1010];
 35 
 36 bool op(node a,node b)
 37 {
 38     if (a.a==b.a) return a.c<b.c;
 39     else return a.a<b.a;
 40 }
 41 
 42 node ntoh(int a,int b,double c)
 43 {
 44     node x;
 45     x.a=a;
 46     x.b=b;
 47     x.c=c;
 48     return x;
 49 }
 50 
 51 double maxx[1010][1010];
 52 bitset<1010> inway[1010];
 53 
 54 double prim(int s,int n)
 55 {
 56     /**/
 57     int list[1010],listail=1;
 58     list[1]=s;
 59     /**/
 60     priority_queue<node> heap;
 61     while (!heap.empty()) heap.pop();
 62     bitset<1010> flag;
 63     flag.reset();
 64     flag[s]=1;
 65     double ans=0;
 66     memset(maxx,0,sizeof(maxx));
 67     for (int i=0;i<num[s];i++) heap.push(edge[start[s]+i]);
 68 
 69     for (int i=1;i<n;i++)
 70     {
 71         node now=heap.top();
 72         heap.pop();
 73         while (flag[now.b])
 74         {
 75             now=heap.top();
 76             heap.pop();
 77         }
 78         /**/
 79         for (int j=1;j<=listail;j++) 
 80         {
 81             maxx[list[j]][now.b]=max(maxx[list[j]][now.a],now.c);
 82             maxx[now.b][list[j]]=maxx[list[j]][now.b];
 83         }
 84         listail++;
 85         list[listail]=now.b;
 86         /**/
 87         flag[now.b]=true;
 88         ans+=now.c;
 89         for (int j=0;j<num[now.b];j++)
 90         if (!flag[edge[start[now.b]+j].b]) heap.push(edge[start[now.b]+j]);
 91     }
 92 
 93     return ans;
 94 }
 95 
 96 double getdis(int x,int y)
 97 {
 98     return sqrt((p[x].x-p[y].x)*(p[x].x-p[y].x)+(p[x].y-p[y].y)*(p[x].y-p[y].y));
 99 }
100 
101 int main()
102 {
103     freopen("4081.txt","r",stdin);
104 
105     int t;
106     scanf("%d",&t);
107     for (int tt=1;tt<=t;tt++)
108     {
109         int n;
110         scanf("%d",&n);
111         for (int i=1;i<=n;i++) scanf("%d%d%d",&p[i].x,&p[i].y,&p[i].p);
112 
113         int m=0;
114         for (int i=1;i<=n;i++)
115         {
116             start[i]=m+1;
117             num[i]=n-1;
118             for (int j=1;j<=n;j++)
119             if (i!=j)
120             {
121                 m++;
122                 edge[m].a=i;
123                 edge[m].b=j;
124                 edge[m].c=getdis(i,j);
125             }
126         }
127         
128         double sum=prim(1,n);
129 
130         double ma=0;
131         for (int i=1;i<=m;i++)
132         {
133             double temp=(p[edge[i].a].p+p[edge[i].b].p)/(sum-maxx[edge[i].a][edge[i].b]);
134             if (ma<temp) ma=temp;
135         }
136 
137         printf("%.2f\n",ma);
138     }
139 
140     return 0;
141 }