1 //#define LOCAL
  2 #include<cstdio>
  3 #include<cstdlib>
  4 #include<cstring>
  5 #include<cmath>
  6 #include<iostream>
  7 #include<algorithm>
  8 using namespace std;
  9 const int maxn=1005;
 10 const int inf=0x3f3f3f3f;
 11 struct node
 12 {
 13  int x,y,p;
 14  double dist(const node &cc){
 15    return sqrt((double)(x-cc.x)*(x-cc.x)+(y-cc.y)*(y-cc.y));
 16  }
 17 }sac[maxn];
 18 
 19 bool vis[maxn];
 20 bool road[maxn][maxn];
 21 int pre[maxn];
 22 double maxc[maxn][maxn];
 23 double lowcost[maxn];
 24 double map[maxn][maxn];
 25 double res;
 26 void prim(int st,int en){
 27 
 28   memset(vis,0,sizeof(vis));
 29   memset(road,0,sizeof(road));
 30   memset(maxc,0,sizeof maxc);
 31   for(int i=0;i<en;i++){
 32        lowcost[i]=map[st][i];
 33      pre[i]=st;;
 34   }
 35   vis[st]=1;
 36   res=0;
 37   for(int i=0;i<en;i++)
 38   {
 39       double larger=inf;
 40       int pp=-1;
 41       for(int j=0;j<en;j++)
 42     {
 43         if(!vis[j]&&larger>lowcost[j])
 44         {
 45             larger=lowcost[j];
 46             pp=j;
 47         }
 48     }
 49     if(-1==pp)continue;
 50       road[pp][pre[pp]]=road[pre[pp]][pp]=1;
 51      res+=lowcost[pp];
 52      vis[pp]=1;
 53     for(int i=0;i<en;i++)
 54     {
 55 
 56         if(!vis[i]&&lowcost[i]>map[pp][i]){
 57             lowcost[i]=map[pp][i];
 58             pre[i]=pp;
 59         }
 60         //求解生成树的最大边
 61          if(vis[i]&&i!=pp){
 62           maxc[i][pp]=maxc[pp][i]=max(maxc[i][pre[pp]],lowcost[pp]);
 63         }
 64     }
 65   }
 66   return ;
 67 }
 68 
 69 int main()
 70 {
 71   #ifdef LOCAL
 72      freopen("test.in","r",stdin);
 73   #endif
 74    int tt,nn;
 75    scanf("%d",&tt);
 76   while(tt--){
 77       scanf("%d",&nn);
 78   //    memset(map,0,sizeof(map));
 79     for(int i=0;i<nn;i++){
 80        scanf("%d%d%d",&sac[i].x,&sac[i].y,&sac[i].p);
 81         map[i][i]=0;
 82        for(int j=i-1;j>=0;--j){
 83          map[i][j]=map[j][i]=sac[i].dist(sac[j]);
 84        }
 85     }
 86     prim(0,nn);
 87     double ans=0.0;
 88    for(int i=0;i<nn;i++){
 89       for(int j=0;j<nn;j++){
 90           if(i!=j)
 91         {
 92             double tol_p=sac[i].p+sac[j].p;
 93            if(road[i][j])
 94                 ans=max(tol_p/(res-map[i][j]),ans);
 95            else
 96                 ans=max(tol_p/(res-maxc[i][j]),ans);
 97         }
 98       }
 99    }
100    printf("%.2lf\n",ans);
101   }
102   return 0;
103 }