#include <bits/stdc++.h>
using namespace std;
const int e = 1e5 + 9;
const long double o = 0.0000000001;
int ceil(int n, int k) {
  if (n % k == 0) {
    return n / k;
  }
  return n / k + 1;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long double n, m, v1, v2, k;
  cin >> n >> m >> v1 >> v2 >> k;
  long double l = 0, r = m + 1;
  for (int i = 0; i < 300; i++) {
    long double mid = (l + r) / 2;
    long double f = ceil(n, k);
    long double t = (m - v1 * mid) / (v2 - v1);
    if (f * t + (f - 1) * ((v2 - v1) * t / (v1 + v2)) < mid) {
      r = mid;
    } else {
      l = mid;
    }
  }
  cout << setprecision(10) << fixed << l << endl;
  return 0;
}
