#include <iostream>
#include <iomanip>
#include <fstream>
#include <map>
using namespace std;

int main()
{
  cout<<setiosflags(ios::fixed)<<setprecision(10);
  ifstream cin("lazy.in");
  for (int n;cin>>n,n!=0;){
    multimap<pair<int,int>,int> jobs;
    for (int i=0;i<n;i++){
      int a,b,d;cin>>a>>b>>d;
      jobs.insert(make_pair(make_pair(d,-a),b));
    }
    multimap<int,double> q;
    double cur=0;
    double ans=0;
    for (multimap<pair<int,int>,int>::iterator p=jobs.begin();
         p!=jobs.end();p++){
      int a=-p->first.second,b=p->second,d=p->first.first;
      cur+=b;
      q.insert(make_pair(-a,b));
      
      while(cur>d){
        int aa=-q.begin()->first;
        double bb=q.begin()->second;
        q.erase(q.begin());
        double rest=cur-d;
        if (rest<bb){
          bb-=rest;
          cur=d;
          ans+=rest/aa;
          q.insert(make_pair(-aa,bb));
        }
        else{
          cur-=bb;
          ans+=bb/aa;
        }
      }
    }
    cout<<ans<<endl;
  }
  return 0;
}