#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, l, v1, v2, k;
  cin >> n >> l >> v1 >> v2 >> k;
  int c = 0;
  if (n % k == 0) {
    c = n / k;
  } else {
    c = n / k + 1;
  }
  long double ans, f, d;
  d = (long double)l * (v1 + v2) / ((2 * c - 1) * v1 + v2);
  ans = d / v2 + (l - d) / v1;
  cout << setprecision(15) << (long double)ans << endl;
  return 0;
}
