#include <bits/stdc++.h>

using namespace std;

int main(void) {
  int n, m, p;
  while (cin >> n >> m >> p, n) {
    vector<int> x(n);
    int sum = 0;
    for (int i = 0; i < n; i++) {
      cin >> x[i];
      sum += x[i];
    }
    sum *= 100 - p;

    cout << (x[m - 1] ? sum / x[m - 1] : 0) << endl;
  }

  return 0;
}
