#include <bits/stdc++.h>
using namespace std;
long long n;
long double k;
long double a[10001];
long double f(long double x) {
  long double smaller = 0.0, bigger = 0.0;
  for (long long i = 0; i < n; i++) {
    if (a[i] <= x) {
      smaller += x - a[i];
    } else {
      bigger += a[i] - x;
    }
  }
  return smaller / bigger;
}
signed main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cin >> n >> k;
  k = 100.0 - k;
  for (long long i = 0; i < n; i++) {
    cin >> a[i];
  }
  long double l = 0.0, r = 1000.0;
  long long cnt = 400;
  while (cnt--) {
    long double mid = (l + r) / 2.0;
    if (f(mid) >= k / 100.0) {
      r = mid;
    } else {
      l = mid;
    }
  }
  cout << fixed << setprecision(9) << r;
  return 0;
}
