#include <stdio.h>

int main(void){

  int n,m,p,x[100];
  int i;

  for(;;){

    scanf("%d %d %d",&n,&m,&p);
    if(n==0 && m==0 && p==0)break;

    int pool=0;

    for(i=0;i<n;i++){
      scanf("%d",&x[i]);
      pool += 100 * x[i];
    }

    if(x[m-1]==0)printf("0\n");
    else printf("%d\n",(pool*(100-p))/(100*x[m-1]));


  }

  return 0;
}