#include <bits/stdc++.h>
using namespace std;
int n;
int k;
long double v1, v2, d;
long double f(long double cnt, long double d) {
  long double res = 0;
  long double t = d / v2;
  long double dif = t * v2 - t * v1;
  return cnt * (d / v2) + (cnt - 1) * (dif / (v2 + v1));
}
long double can(long double x) {
  int cnt = n / k;
  if (n % k) cnt++;
  long double t2 = (d - x) / v1;
  return f(cnt, x) < t2 + x / v2;
}
int main() {
  long double ans = 0;
  cin >> n >> d >> v1 >> v2 >> k;
  long double l = 0;
  long double r = d;
  while (r - l > 0.0000000001) {
    long double mid = (l + r) / 2.;
    if (can(mid))
      l = mid;
    else
      r = mid;
  }
  cout.precision(9);
  cout << fixed << l / v2 + (d - l) / v1 << "\n";
}
