#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k;
  double l, v1, v2;
  scanf("%d%lf%lf%lf%d", &n, &l, &v1, &v2, &k);
  int num = n / k;
  if (num * k < n) {
    num++;
  }
  double w = (v1 + v2) * v2 / (2 * v1 * v2 * num + v2 * v2 - v1 * v2) * l;
  double t = w / v2 + (l - w) / v1;
  printf("%.10lf\n", t);
}
