// horizon
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <list>
#include <set>
#include <map>
#include <algorithm>
#include <functional>
#include <cstdio>

using namespace std;

#define foreach(T, p, c) for(T p = (c).begin(); p != (c).end(); ++p)

struct slope {
  int Eff;
  int Len;
  int From;
  slope(){}
  slope(int f, int e, int l){
    Eff = e;
    Len = l;
    From = f;
  }
  slope(int f, int t, int s, int l){
    if(s >= 60){
      Eff = 10 * l;
    }else{
      Eff = (70 - s) * l;
    }
    Len = l;
    From = f;
  }
  double AEff() const{
    return ((double)Eff / (double)Len);
  }
};

bool operator <(const slope &a, const slope &b){
  double da = ((double)a.Eff / (double)a.Len);
  double db = ((double)b.Eff / (double)b.Len);
  return (da < db);
}

int N, R, S, D;
vector<slope> Flat[120]; 
set<slope> Path[120];

void insert(int dest, slope p){
  foreach(set<slope>::iterator, q, Path[dest]){
    if((p.AEff() >= q->AEff()) && (p.Len <= q->Len)){
      return;
    }
  }
  Path[dest].insert(p);
}

void solve(int dest){
  if(dest == S){ return; }
  if(Path[dest].size() == 0){
    foreach(vector<slope>::iterator, p, Flat[dest]){
      int f = p->From;
      if(f == S){
	Path[dest].insert(*p);
      }else{
	solve(f);
	// set<slope>::iterator q = Path[f].begin();
	foreach(set<slope>::iterator, q, Path[f]){
	  insert(dest, slope(q->From, p->Eff + q->Eff, p->Len + q->Len));
	// Path[dest].insert(slope(q->From, p->Eff + q->Eff, p->Len + q->Len));
        }
      }
    }
  }
}

int main()
{
  ifstream cin("ski.txt");
  int T;

  cin >> T;
  for(int iii=0; iii<T; iii++){
    for(int i=0; i<120; i++){
      Flat[i].clear();
      Path[i].clear();
    }
    cin >> N >> R >> S >> D;
    for(int i=0; i<R; i++){
      int f, t, s, l;
      cin >> f >> t >> s >> l;
      Flat[t].push_back(slope(f, t, s, l));
    }
    solve(D);
    slope slp = *(Path[D].begin());
    double deff = ((double)slp.Eff / (double)slp.Len);
    // cout << slp.Eff << " " << slp.Len << " " <<  deff << endl;
    printf("%.2f\n", deff);
  }
}