#include <cstdio>
#include <cstdlib>
#include <vector>
#include <algorithm>
/*電子音が好き*/
using namespace std;
const int MAXN=1011;
const int Root=1;
vector<int> map[MAXN],val[MAXN];
int N,W,D,T;double ans;

inline void clear()
{
	W=0,D=0,ans=0;
	for(int i=1;i<=N;i++) 
		map[i].clear(),val[i].clear();
}

void dfs(int k,int f)
{
	int tmp;double tans;
	for(unsigned int i=0;i<map[k].size();i++)
	{
		tmp=map[k][i];if(tmp==f) continue;
		W+=val[k][i],D++; tans=(double(W)/double(D));
		if(tans>ans) ans=tans; dfs(tmp,k);
		W-=val[k][i],D--;
	}
} 

int main()
{
	freopen("treec.in","r",stdin);
	freopen("treec.out","w",stdout);
	scanf("%d\n",&T);int x,y,z;
	for(int k=1;k<=T;k++)
	{
		scanf("%d\n",&N); clear();
		for(int i=1;i<=N-1;i++)
		{
			scanf("%d %d %d\n",&x,&y,&z);
			x++,y++;
			map[x].push_back(y);val[x].push_back(z);
			map[y].push_back(x);val[y].push_back(z);
		}
		if(int(map[Root].size())==0) 
		{
			printf("%.5lf\n",ans);
			continue;
		} dfs(Root,0);
		printf("%.5lf\n",ans);
	}
	return 0;
}