int main()
{
  int n,m,p,i,x,sum,win;
  for(;scanf("%d%d%d",&n,&m,&p),n;)
    {
      sum=0;
      for(i=1;i<=n;i++)
	{
	  scanf("%d",&x);
	  sum+=(x*100);
	  if(i==m)
	    win=x;
	}
      if(win==0)
	puts("0");
      else
	printf("%.f\n",(sum*((100-p)/(double)100))/win);
    }
  exit(0);
}