#include<stdio.h>

int main(){
  int i;
  int N,M;
  double P;
  int X[1001];
  int num;

  while(1){
    num=0;
    scanf("%d %d %lf",&N,&M,&P);
    if(N==0&&M==0&&P==0) break;

    for(i=0;i<1001;i++){
      X[i]=0;
    }

    for(i=1;i<=N;i++){
      scanf("%d",&X[i]);
      num+=100*X[i];
    }

    num-=num*(P/100);

    if(X[M]==0) printf("0\n");
    else printf("%d\n",num/X[M]);
  }

  return 0;
}