#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, l, v1, v2, k;
  scanf("%lld%lld%lld%lld%lld", &n, &l, &v1, &v2, &k);
  int num = (n - 1) / k;
  double t = 2.0 * l / (v1 + v2 + 2 * num * v1);
  double s = num * t * v1;
  double ans = s / v1 + (l - s) / v2;
  printf("%.10f\n", ans);
}
