#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, kk;
  double time, s, temp;
  double l, v1, v2, k;
  cin >> n >> l >> v1 >> v2 >> m;
  double aa, bb;
  kk = n / m;
  if (n % m) kk++;
  k = kk;
  aa = l;
  bb = (k - 1) * v1 + (v1 + v2) / 2;
  double t = (aa / bb);
  time = (k - 1) * t + t * (v1 + v2) / 2 / v2;
  printf("%.10lf", time);
  return 0;
}
