#include <bits/stdc++.h>
using namespace std;
int a[10010];
int main() {
  double best = 0;
  int n, k;
  scanf("%d%d", &n, &k);
  double sum = 0;
  for (int i = (0); i < (n); ++i) {
    scanf("%d", &a[i]);
    sum += a[i];
  }
  double l = 0, r = 100000000;
  for (int it = (0); it < (200); ++it) {
    double m = (l + r) / 2;
    double sum1 = 0, sum2 = 0;
    for (int i = (0); i < (n); ++i) {
      if (a[i] < m) {
        double p = m - a[i];
        sum1 += (100 * p) / (double)(100 - k);
      } else
        sum2 += a[i] - m;
    }
    if (sum1 <= sum2) {
      best = m;
      l = m;
    } else
      r = m;
  }
  printf("%.8lf\n", best);
  return 0;
}
