#include <bits/stdc++.h>
using namespace std;
int n, k, a[10005];
int f(double q) {
  int j;
  double sum = 0, s = 0, t;
  for (j = 0; j < n; j++) {
    if ((double)a[j] < q) {
      sum += q - (double)a[j];
    } else {
      s += (double)a[j] - q;
    }
  }
  if (s - s * (double)(k) / (100.0) > sum) {
    return 1;
  } else {
    return 0;
  }
}
void solve() {
  int i, j;
  double l = 0, r = 1e8;
  for (i = 0; i < n; i++) {
    scanf("%d", &a[i]);
  }
  while (r - l > 0.0000001) {
    if (f((r + l) / 2) == 1) {
      l = (r + l) / (2.0);
    } else {
      r = (r + l) / (2.0);
    }
  }
  if (f(r) == 1) {
    printf("%.10lf", r);
  } else {
    printf("%.10lf", l);
  }
  return;
}
int main() {
  scanf("%d%d", &n, &k);
  solve();
  return 0;
}
