#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:136777216")
using namespace std;
int bits(int n, int x) { return x == 0 ? 0 : 1 + bits(n, x & (x - 1)); }
int main() {
  int n, k;
  cin >> n >> k;
  vector<int> v(n);
  for (int(i) = 0; (i) < (n); (i)++) scanf("%d", &v[i]);
  double l = 0, r = 1000;
  for (int(zz) = 0; (zz) < (100); (zz)++) {
    double x = (l + r) / 2, need = 0, more = 0;
    for (int(i) = 0; (i) < (n); (i)++)
      if (v[i] < x)
        need += x - v[i];
      else
        more += v[i] - x;
    need *= 100. / (100 - k);
    if (need > more)
      r = x;
    else
      l = x;
  }
  printf("%.10lf", r);
  return 0;
}
