#include <bits/stdc++.h>
using namespace std;
long double n, l, k, v1, v2;
int main() {
  cout << fixed << setprecision(10);
  cin >> n >> l >> v1 >> v2 >> k;
  if (v2 <= v1) {
    cout << l / (v1 * 1.0) << endl;
    return 0;
  }
  if (n <= k) {
    cout << l / (v2 * 1.0) << endl;
    return 0;
  }
  int T = ceil(n / (k * 1.0));
  long double K = ((T - 1) * (1 + (v2 - v1) / ((v2 + v1) * 1.0))) * v1;
  K += v2;
  K = l / K;
  long double ans = K * (T + (T - 1) * (v2 - v1) / (v2 + v1));
  cout << ans << endl;
}
