#include <stdio.h>
#include <math.h>

int solve(int N, int M, int P){
  int i, buf, sum = 0;
  int x[N];
  double prize;
  for(i = 0; i < N; i++){
    scanf("%d", &buf);
    x[i] = buf;
    sum += buf;
  }
  
  prize = sum * (100 - P);
  if(x[M - 1] == 0) return 0;
  prize /= x[M - 1];
  
  prize = floor(prize);
  
  return (int)prize;
}

int main(void){
  int N, M, P;
  while(1){
    scanf("%d %d %d", &N, &M, &P);
    if(N == 0 && M == 0 && P == 0) break;
    printf("%d\n", solve(N, M, P));
  }
  return 0;
}
