#include <bits/stdc++.h>
using namespace std;
long n, l, v1, v2, k;
int main() {
  scanf("%ld%ld%ld%ld%ld", &n, &l, &v1, &v2, &k);
  long tmp = n / k;
  if (n % k) ++tmp;
  double x, c, res;
  x = 2.0 * (tmp - 1) * v1 / (v1 + v2) + 1;
  c = l / x;
  res = 2.0 * (tmp - 1) * c / (v1 + v2) + c / v2;
  printf("%lf", res);
}
