#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, l, v1, v2, k;
  cin >> n >> l >> v1 >> v2 >> k;
  int r = n / k + (n % k > 0);
  double l1 =
      ((double)(l)) /
      ((double)(v1 * (r / ((double)(v2 - v1)) + (r - 1) / ((double)(v2 + v1))) +
                1));
  cout << setprecision(20) << (l - l1) / v1;
}
