#include <bits/stdc++.h>
using namespace std;
signed int main() {
  signed long long n, l, v1, v2, k;
  cin >> n >> l >> v1 >> v2 >> k;
  signed int na = (signed int)ceil(1.0 * n / k) - 1;
  double b = 1.0 * l * (v1 + v2) / (v1 + v2 + 2 * na * v1);
  double ans = b / v2 + (l - b) / v1;
  cout << setprecision(16) << ans << endl;
  return 0;
}
