import java.io.*;
import java.util.*;
import java.text.*;

class Contract{
	int id,a,b,d;
	
	Contract(int id,int a,int b,int d){
		this.id=id;
		this.a =a;
		this.b =b;
		this.d =d;
	}
}

class CompByD implements Comparator{
	public int compare(Object o1,Object o2){
		Contract c1=(Contract)o1,c2=(Contract)o2;
		return c1.d!=c2.d ? c1.d-c2.d : c1.id-c2.id;
	}
}
class CompByA implements Comparator{
	public int compare(Object o1,Object o2){
		Contract c1=(Contract)o1,c2=(Contract)o2;
		return c1.a!=c2.a ? c1.a-c2.a : c1.id-c2.id;
	}
}

public class Lazy_nomura{
	public static void main(String[] args) throws Exception{
		BufferedReader br=new BufferedReader(new FileReader("lazy.in"));
		StringTokenizer st;
		int i,j,k,l;
		
		while(true){
			int n=Integer.parseInt(br.readLine());
			if(n==0) break;
			
			Contract[] cs=new Contract[n];
			
			for(i=0;i<n;i++){
				st=new StringTokenizer(br.readLine());
				int a=Integer.parseInt(st.nextToken());
				int b=Integer.parseInt(st.nextToken());
				int d=Integer.parseInt(st.nextToken());
				
				cs[i]=new Contract(i,a,b,d);
			}
			
			Arrays.sort(cs,new CompByD());
			
			double ans=0;
			int bSum=0;
			TreeSet pque=new TreeSet(new CompByA());
			for(i=0;i<n;i++){
				pque.add(cs[i]);
				
				bSum+=cs[i].b;
				while(bSum>cs[i].d){
					int over=bSum-cs[i].d;
					
					Contract cMaxA=(Contract)pque.last();
					if(cMaxA.b>over){
						ans+=(double)over/cMaxA.a;
						cMaxA.b-=over;
						bSum=cs[i].d;
					}
					else{
						ans+=(double)cMaxA.b/cMaxA.a;
						pque.remove(cMaxA);
						bSum-=cMaxA.b;
					}
				}
			}
			
			DecimalFormat df=new DecimalFormat("0.00");
			System.out.println(df.format(ans));
		}
	}
}