#include <bits/stdc++.h>
using namespace std;
int n, k;
int T[10007];
const double EPS = 1e-7;
int check(double t) {
  double power = 0;
  for (int i = 0; i < n; i++) {
    if (T[i] > t) power += T[i] - t;
  }
  power -= power * ((double)k / 100);
  for (int i = 0; i < n; i++) {
    if (t > T[i]) power -= t - T[i];
  }
  if ((power < EPS) && (power > -EPS))
    return 0;
  else if (power < 0)
    return 1;
  else
    return 2;
}
int main() {
  scanf("%d %d", &n, &k);
  for (int i = 0; i < n; i++) {
    scanf("%d", &T[i]);
  }
  double up = 1000;
  double down = 0;
  while (true) {
    double delta = (up + down) / 2;
    int ret = check(delta);
    if (ret == 0) {
      printf("%.10f", delta);
      return 0;
    }
    if (ret == 1) up = delta;
    if (ret == 2) down = delta;
  }
  return 0;
}
