#include <bits/stdc++.h>
using namespace std;
const double LIM = 1e-6;
int n, k;
double length, walk, bus;
bool get(double time) {
  int rem = n;
  double clock = 0.0;
  double dist = length;
  while (rem > 0) {
    if (dist / bus + clock > time) {
      return false;
    }
    rem = max(0, rem - k);
    double go = (walk * (time - clock) - dist) / (walk - bus);
    double back = go * ((bus - walk) / (bus + walk));
    clock += go + back;
    dist -= walk * (go + back);
  }
  return true;
}
double search(double l, double r) {
  double m = (l + r) / 2.0;
  if (r - m < LIM) {
    return m;
  } else if (get(m)) {
    return search(l, m);
  } else {
    return search(m, r);
  }
}
int main() {
  scanf("%d %lf %lf %lf %d", &n, &length, &walk, &bus, &k);
  printf("%.10f", search(0.0, length / walk));
}
