///combax
#include <fstream>
#include <iostream>
#include <map>
#include <set>
using namespace std;

bool hasbetter(set<pair<int,int> > s,pair<int,int> c ){
  for(set<pair<int,int> >::iterator it= s.begin();it!=s.end();it++){
    if(it->first<=c.first && it->second>=c.second)
      return true;
  }
  return false;
}

double best(set<pair<int,int> > s){
  double ret=12345678956;
  for(set<pair<int,int> >::iterator it= s.begin();it!=s.end();it++){
    ret= min((it->first / (double)(it->second+0.00000001)),ret);
  }
  return ret;
}
int main()
{
  ifstream cin("ski.txt");
  int cases;
  cin>>cases;
  for(;cases--;){
    int n,r,sta,end;
    cin >> n >> r >> sta >> end;
    int i;
    int cost[102][102]={0},dist[102][102]={0};
    for(int i=0;i<r;i++){
      int s,e,spd,d;
      cin >> s >> e >> spd >> d;
      dist[s-1][e-1]=d;
      cost[s-1][e-1]=((s<=60)? (d*(70-spd)) : (d*(spd-50)));
    }
    set<pair<int,pair<int ,int > > > q;
    set<pair<int,int> > cand[100];
    q.insert(make_pair(sta-1,make_pair(0,0)));
    while(!q.empty()){
      pair<int,pair<int ,int > > p = *q.begin();
      q.erase(q.begin());
      if (hasbetter(cand[n],p.second)) continue;
      int h=p.first,c=p.second.first,d=p.second.second;
//      cout << h << " " << c << " " << d << endl;
      cand[h].insert (p.second);
      for(int k=0;k<n;k++){
        if(dist[h][k]){
          q.insert(make_pair(k,make_pair(c+cost[h][k],d+dist[h][k])));
          //cout << k << endl;
        }
      }
    };
     printf("%.2f\n", best(cand[end-1]));
  }
  return 0;
}