#include <bits/stdc++.h>
using namespace std;
const double esp = 0.00000005;
double l, v1, v2;
int n, k;
bool check(double t) {
  double t2 = (l - v1 * t) / (v2 - v1);
  double t1 = t - t2;
  if (t1 < 0 || t2 < 0) return false;
  double d = ((v2 * t2 - v1 * t2) / (v1 + v2) + t2) * v1;
  int c = n / k;
  if (c * k != n) c++;
  return d * (c - 1) + t2 * v2 - l < esp;
}
int main() {
  cin >> n >> l >> v1 >> v2 >> k;
  double L = 0, R = l / v1;
  int tt = 1000;
  while (R - L > esp) {
    tt--;
    if (tt == 0) break;
    double mid = (R + L) / 2;
    if (check(mid))
      R = mid;
    else
      L = mid;
  }
  printf("%.7f\n", L);
  return 0;
}
