#include <bits/stdc++.h>
using namespace std;
int main() {
  cout.precision(numeric_limits<double>::max_digits10);
  int n, k, m;
  double l, v1, v2, x, time;
  cin >> n >> l >> v1 >> v2 >> k;
  m = (n - 1) / k;
  x = (v1 + v2) * l / (v1 + v2 + 2.0 * v1 * (double)m);
  time = (l - x) / v1 + x / v2;
  cout << time << endl;
  return 0;
}
