#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k;
  double l, v1, v2;
  scanf("%d %lf %lf %lf %d", &n, &l, &v1, &v2, &k);
  double ans;
  if (v1 >= v2)
    ans = l / v1;
  else {
    if (n <= k)
      ans = l / v2;
    else {
      int p = n / k;
      if (n % k != 0) p++;
      double y =
          l / ((p - 1) * v1 * ((v2 - v1) / (v2 + v1)) + p * v1 + v2 - v1);
      ans = y + (l - y * v2) / v1;
    }
  }
  printf("%0.10lf\n", ans);
  return 0;
}
