//GNC
#include<iostream>
#include<string>
#include <vector>
#include <algorithm>
#include <map>
#include <set>
#include <fstream>
#include <sstream>
#include <queue>
#include <iomanip>

using namespace std;

struct job{
  int efficiency, needtime, deadline;
  job(){}
  job(int e, int n, int d): efficiency(e), needtime(n), deadline(d) {}
};

bool jobless (const job& lhs, const job& rhs)
{
  return lhs.deadline < rhs.deadline;
}

typedef pair<int,int> gojob;

int main(void)
{
  int N;
  ifstream cin("lazy.in");
  while(cin >> N && N){
    vector<job> alljobs;
    for(int i = 0; i < N; ++i){
      job j;
      cin >> j.efficiency >> j.needtime >> j.deadline;
      alljobs.push_back(j);
    }
    sort(alljobs.begin(), alljobs.end(), jobless);
    int currenttime = 0;
    double currentmoney = 0;
    priority_queue<gojob> gojobs;
    for(int i = 0 ; i < N ; i ++){
      struct job curjob = alljobs[i];
      gojobs.push(make_pair(curjob.efficiency,curjob.needtime));
      int rest = curjob.needtime + currenttime - curjob.deadline;
      while(rest > 0){
	gojob top = gojobs.top();
	gojobs.pop();
	if(top.second > rest){
	  currentmoney += (double)rest / top.first;
	  top.second -= rest;
	  rest = 0;
	  gojobs.push(top);
	}else{
	  currentmoney += (double)top.second / top.first;
	  rest -= top.second;
	}
      }
      currenttime = curjob.deadline+rest;
    }
    cout.setf(ios::fixed);
    cout << setprecision(3);
    cout << currentmoney << endl;
  }
}