#include <bits/stdc++.h>
using namespace std;
double N, K, L, t, v1, v2, s, e, m, z, a;
double f(double x) {
  double d = x / v2;
  double p = (x - d * v1) / (v1 + v2);
  return t * d + (t - 1) * p;
}
int main() {
  cin >> N >> L >> v1 >> v2 >> K;
  t = ceil(N / K);
  s = 0, e = L;
  while (e - s > 1e-10) {
    m = (s + e) / 2;
    if (f(m) < m / v2 + (L - m) / v1)
      s = m;
    else
      e = m;
  }
  z = e / v2;
  a = (L - e) / v1;
  z += a;
  printf("%.10lf\n", z);
}
