#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k;
  double l, r, mid;
  cin >> n >> k;
  vector<double> a(n);
  l = 1000;
  r = 0;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    if (a[i] > r) r = a[i];
    if (a[i] < l) l = a[i];
  }
  while (l <= r) {
    double sum = 0;
    mid = (r + l) / 2;
    for (int i = 0; i < n; i++) {
      if (mid > a[i])
        sum -= (mid - a[i]) * 100 / (100 - k);
      else
        sum += (a[i] - mid);
    }
    if (sum <= 0.000000001 && sum >= -0.000000001)
      break;
    else {
      if (sum > 0.000000001)
        l = mid;
      else
        r = mid;
    }
  }
  cout << fixed << setprecision(9) << mid << endl;
}
