#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, l, v1, v2, k;
  cin >> n >> l >> v1 >> v2 >> k;
  int g = n / k + (n % k == 0 ? 0 : 1);
  double ans = (double)l / (double)v1;
  double t =
      (double)(v1 + v2) * l / (double)(v2 * (2 * (double)v1 * g - v1 + v2));
  ans = min(ans, t + (double)(l - v2 * t) / (double)v1);
  printf("%.8lf", ans);
  return 0;
}
