#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k, a[10001];
  cin >> n >> k;
  double left = 0, right = 1000.0, x = 0, y = 0;
  for (int i = 0; i < n; ++i) cin >> a[i];
  while (left + 1E-9 < right) {
    x = 0, y = 0;
    double mid = (left + right) / 2;
    for (int i = 0; i < n; ++i) {
      if (a[i] < mid)
        x += mid - a[i];
      else
        y += a[i] - mid;
    }
    if (x * 100 < y * (100 - k))
      left = mid;
    else
      right = mid;
  }
  printf("%.6lf\n", left);
}
