#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  double l, x, v1, v2, k;
  cin >> l >> x >> v1 >> v2 >> k;
  double n = ceil(l / k);
  double t2, t1;
  t2 = x / (v2 * (n * ((v1 + v2) / (v2 - v1)) - (n - 1)));
  t1 = t2 * (v1 + v2) / (v2 - v1);
  double odp = t1 * n + t2 * (n - 1);
  cout << setprecision(8) << odp;
}
