#include <bits/stdc++.h>
using namespace std;
const long long maxn = (long long)1e5 + 9;
const long long mod = (long long)1e9 + 7;
int main() {
  std::ios::sync_with_stdio(0);
  long long i, j, k, t, q, m, l, r, n, v1, v2;
  cin >> n >> l >> v1 >> v2 >> k;
  long long g = (n / k) + (n % k > 0);
  double d, time;
  d = (double)((v1 + v2) * l) / ((2 * v1 * g) - v1 + v2);
  time = (2 * d * g - l) / (v2);
  cout << setprecision(11) << time << '\n';
}
