#include <bits/stdc++.h>
using namespace std;
int n, k, a[10100];
int main() {
  scanf("%d%d", &n, &k);
  for (int i = 0; i < (n); i++) scanf("%d", &a[i]);
  double l = 0, r = *max_element(a, a + n), x;
  while (r - l > 1e-7) {
    x = (l + r) / 2;
    double q = 0;
    for (int i = 0; i < (n); i++)
      if (a[i] + 1e-7 >= x)
        q += (a[i] - x) - (a[i] - x) * k / 100;
      else
        q -= x - a[i];
    if (q + 1e-7 > 0)
      l = x;
    else
      r = x;
  }
  printf("%.7lf", l);
}
