#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 5;
int n, l, v1, v2, k;
bool tmam(long double t) {
  long double time_in_bus = (1.00 * l - t * v1) / (1.00 * (v2 - v1));
  if (time_in_bus < 0) return 1;
  int kam = n / k;
  if (n % k) kam++;
  long double dis = l - t * v1;
  long double z = dis / (v2 + v1);
  if (time_in_bus * kam + z * (kam - 1) <= t) return 1;
  return 0;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> l >> v1 >> v2 >> k;
  long double low = 0, high = 1e9, mid;
  for (int i = 0; i < 1000; i++) {
    mid = low + (high - low) / 2;
    if (tmam(mid)) {
      high = mid;
    } else
      low = mid;
  }
  cout << fixed << setprecision(10) << mid;
  return 0;
}
