#include <cstdlib>
#include <cctype>
#include <cstring>
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <vector>
#include <string>
#include <iostream>
#include <sstream>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <fstream>
#include <numeric>
#include <iomanip>
#include <bitset>
#include <list>
#include <stdexcept>
#include <functional>
#include <utility>
#include <ctime>
#include <cassert>
#include <complex>
using namespace std;
#define rep(i,a,n) for (int i=a;i<n;i++)
#define per(i,a,n) for (int i=n-1;i>=a;i--)
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
#define ACCU accumulate
#define TWO(x) (1<<(x))
#define TWOL(x) (1ll<<(x))
#define clr(a) memset(a,0,sizeof(a))
#define POSIN(x,y) (0<=(x)&&(x)<n&&0<=(y)&&(y)<m)
#define PRINTC(x) cout<<"Case #"<<++__<<": "<<x<<endl 
#define POP(x) (__builtin_popcount(x))
#define POPL(x) (__builtin_popcountll(x))
typedef vector<int> VI;
typedef vector<string> VS;
typedef vector<double> VD;
typedef long long ll;
typedef long double LD;
typedef pair<int,int> PII;
typedef pair<ll,ll> PLL;
typedef vector<ll> VL;
typedef vector<PII> VPII;
typedef complex<double> CD;
const int inf=0x20202020;
const ll mod=1000000007;
const double eps=1e-9;
const double pi=3.1415926535897932384626;
const int DX[]={1,0,-1,0},DY[]={0,1,0,-1};
ll powmod(ll a,ll b) {ll res=1;a%=mod;for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
ll powmod(ll a,ll b,ll mod) {ll res=1;a%=mod;for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;}
// head

const int N=210;
vector<pair<int,double> > e[N];
int f[N],p[N],a[N],b[N],u[N],v[N];
int n,m,T,C;
double w[N];
vector<double> mt;
inline bool cmp(const int &a,const int &b) { return w[a]>w[b];}
double dfs(int u,int f,double w) {
    double res=(u==1?0:w);
    rep(i,0,SZ(e[u])) {
        int v=e[u][i].fi;
        if (v==f) continue;
        res+=dfs(v,u,min(w,e[u][i].se));
    }
    return res;
}
int find(int u) { return f[u]==u?u:f[u]=find(f[u]);}
double solve(double t) {
    rep(i,0,m) w[i]=b[i]*t+a[i],p[i]=i;
    sort(p,p+m,cmp);
    rep(i,1,n+1) f[i]=i,e[i].clear();
    int tot=n-1;
    rep(i,0,m) {
        int U=u[p[i]],V=v[p[i]];
        double W=w[p[i]];
        if (find(U)!=find(V)) {
            f[find(U)]=find(V);
            e[U].pb(mp(V,W));
            e[V].pb(mp(U,W));
            --tot;
        }
        if (tot==0) break;
    }
    return dfs(1,0,1e30);
}
int main() {
    for (scanf("%d",&C);C;C--) {
        scanf("%d%d%d",&n,&m,&T);
        rep(i,0,m) scanf("%d%d%d%d",u+i,v+i,a+i,b+i);
        mt.clear();
        rep(i,0,m) rep(j,i+1,m) if (b[i]!=b[j]) {
            double t=1.*(a[j]-a[i])/(b[i]-b[j]);
            if (t>0&&t<T) mt.pb(t);
        }
        mt.pb(T);
        sort(all(mt));
        mt.erase(unique(all(mt)),mt.end());
        double ans=0;
        double pa=solve(0),pt=0;
        rep(i,0,SZ(mt)) {
            double pb=solve(mt[i]);
            ans+=(pa+pb)*(mt[i]-pt)/2;
            pt=mt[i]; pa=pb;
        }
        printf("%.3f\n",ans/T);
    }
}