#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, dist, v1, v2, k;
  cin >> n >> dist >> v1 >> v2 >> k;
  if (n % k)
    n = n / k + 1;
  else
    n /= k;
  if (v1 >= v2) {
    printf("%.10f", double(dist) / v1);
    return 0;
  }
  if (n == 1) {
    printf("%.10f", double(dist) / v2);
    return 0;
  }
  double t1 =
      double(v1 + v2) * dist / (2.0 * v1 * v2 * (n - 1) + double(v1 + v2) * v2);
  double a = v2 * t1;
  double b = dist - a;
  double t2 = b / v1;
  printf("%.10f", t1 + t2);
  return 0;
}
