#include <vector> 
#include <list> 
#include <map> 
#include <set> 
#include <deque> 
#include <queue> 
#include <stack> 
#include <bitset> 
#include <algorithm> 
#include <functional> 
#include <numeric> 
#include <utility> 
#include <sstream> 
#include <iostream> 
#include <iomanip> 
#include <cstdio> 
#include <cmath> 
#include <cstdlib> 
#include <cctype> 
#include <string> 
#include <cstring> 
#include <ctime> 

using namespace std;

#define _int64 long long

struct edge
{
  int x,y,a,b;
};

vector<edge> a;
vector<pair<int,int> > ti;
double now;
int pp[100];
int used[100];

bool pcmp(pair<int,int> a,pair<int,int> b)
{
  return a.first*b.second<b.first*a.second;
}

bool pcmp1(edge a,edge b)
{
  return a.a+a.b*now<b.a+b.b*now;
}

int main()
{
  int i,j,l,t,n,m,time,tmp,k;
  double ans,x1,x2;
  edge p;
  scanf("%d",&t);
  for (l=0;l<t;l++)
  {
    scanf("%d%d%d",&n,&m,&time);
    a.clear();
    for (i=0;i<m;i++)
    {
      scanf("%d%d%d%d",&p.x,&p.y,&p.a,&p.b);
      p.x--;p.y--;
      a.push_back(p);
    }
    //cout<<a.size()<<endl;
    ti.clear();
    for (i=0;i<m;i++)
      for (j=i+1;j<m;j++)
      {
        if (a[i].b==a[j].b) continue;
        if ((a[i].a-a[j].a)*(a[j].b-a[i].b)<=0) continue;
        ti.push_back(make_pair(a[i].a-a[j].a,a[j].b-a[i].b));
        if (ti[ti.size()-1].first<0)
        {
          ti[ti.size()-1].first=-ti[ti.size()-1].first;
          ti[ti.size()-1].second=-ti[ti.size()-1].second;
        }
      }
    ti.push_back(make_pair(0,1));
    //ti.push_back(make_pair(0,2));
    ti.push_back(make_pair(10000,1));
    //cout<<ti.size()<<endl;
    sort(ti.begin(),ti.end(),pcmp);
    ti.erase(unique(ti.begin(),ti.end()),ti.end());
    //cout<<ti.size()<<endl;
    ans=0;
    for (i=0;i+1<ti.size();i++)
    {
      x1=(double)ti[i].first/ti[i].second;
      x2=(double)ti[i+1].first/ti[i+1].second;
      if (x2-x1<1e-9) continue;
      if (time<x2) x2=time;
      //cout<<x1<<" "<<x2<<endl;
      now=(x1+x2)/2;
      sort(a.begin(),a.end(),pcmp1);
      reverse(a.begin(),a.end());
      //for (j=0;j<a.size();j++)
      //  cout<<a[j].x<<" "<<a[j].y<<endl;
      for (j=0;j<n;j++)
        pp[j]=j;
      memset(used,0,sizeof(used));
      for (j=0;j<a.size();j++)
      {
        if (pp[a[j].x]!=pp[a[j].y])
        {
          tmp=pp[a[j].y];
          for (k=0;k<n;k++)
            if (pp[k]==tmp) pp[k]=pp[a[j].x];
          for (k=1;k<n;k++)
            if ((pp[k]==pp[0])&&(used[k]==0))
            {
              used[k]=1;
              ans+=(x2-x1)*(a[j].a+a[j].b*now);
            }
        }
        
      }
      if (time<(double)ti[i+1].first/ti[i+1].second) break;
    }
    printf("%.3lf\n",ans/time);
  }
  return 0;
}