#include <bits/stdc++.h>
using namespace std;
const double eps = 1e-6;
int Solution() {
  int n, k;
  cin >> n >> k;
  vector<int> mas(n);
  for (int i = 0; i < n; ++i) cin >> mas[i];
  sort(mas.rbegin(), mas.rend());
  vector<int> sum(n);
  sum[0] = mas[0];
  for (int i = 1; i < n; ++i) sum[i] = sum[i - 1] + mas[i];
  for (int i = 0; i < n - 1; ++i) {
    double x = (100. * sum[n - 1] - sum[i] * (k * 1.0)) /
               (100. * n - (i + 1) * k * 1.0);
    if (x - eps <= mas[i] && x + eps >= mas[i + 1]) {
      printf("%.7lf\n", x);
      return 0;
    }
  }
  double x =
      (100. * sum[n - 1] - sum[n - 1] * (k * 1.0)) / (100. * n - n * k * 1.0);
  printf("%.7lf\n", x);
  return 0;
}
int main() {
  Solution();
  return 0;
}
