#include <bits/stdc++.h>
using namespace std;
int main() {
  double n, l, v1, v2, k, r, w;
  cin >> n >> l >> v1 >> v2 >> k;
  int a = (int)ceil(n / k);
  r = l / v2 / (a - (a - 1) * (v2 - v1) / (v2 + v1));
  w = (l - r * v2) / v1;
  printf("%.9f\n", w + r);
  return 0;
}
