#include <bits/stdc++.h>
using namespace std;
int main(int argc, char *argv[]) {
  int n, k, j, i, a[10001], s[1002], n1, n2, num[1002], h1, h2;
  double x, sum1, sum2, l, r, m;
  scanf("%d %d", &n, &k);
  h1 = 1000;
  h2 = 0;
  for (i = 0; i < n; i++) {
    cin >> a[i];
    if (h1 > a[i]) h1 = a[i];
    if (h2 < a[i]) h2 = a[i];
  }
  for (i = 0; i <= h2; i++) {
    s[i] = 0;
    num[i] = 0;
  }
  for (i = 0; i < n; i++) {
    for (j = a[i]; j <= h2; j++) {
      s[j] += a[i];
      num[j]++;
    }
  }
  l = h1;
  r = h2;
  while (r - l >= 1e-9) {
    m = (l + r) / 2;
    sum1 = ((double)num[(int)m]) * m - (double)s[(int)m];
    sum2 =
        (double)(s[h2] - s[(int)m]) - (((double)(num[h2] - num[(int)m])) * m);
    if (sum2 * (1 - k / 100.0) > sum1) {
      l = m;
    } else {
      r = m;
    }
  }
  cout.precision(6);
  cout.setf(ios::fixed, ios::floatfield);
  cout << (s[h2] - sum2 * (double)k / 100.0) / (double)n << endl;
  return EXIT_SUCCESS;
}
