#include<stdio.h>
int main()
{
  int n,m,p,i,x[101],t,a;
  double p1;
  while(1){
    t=0;
    scanf("%d%d%d",&n,&m,&p);
    if(n==0)break;
    p1=(100-p)/100.0;
    for(i=1;i<=n;i++){
      scanf("%d",&x[i]);
	t=t+x[i];
    }
        if(x[m]==0){
      printf("0\n");
    }
    else{
   a=p1*100*t/x[m];
   printf("%d\n",a);
  }
  }
  return 0;
}