#include <bits/stdc++.h>
int main() {
  int n, v1, v2, seats, distance;
  scanf("%d %d %d %d %d", &n, &distance, &v1, &v2, &seats);
  int times;
  if (n % seats == 0) {
    times = n / seats - 1;
  } else {
    times = (int)(n / (double)seats);
  }
  int64_t bv1, bv2;
  bv1 = v1;
  bv2 = v2;
  double fd =
      2 * times * bv1 * distance / (double)(2 * times * bv1 + bv1 + bv2);
  double secs = (distance - fd) / bv2 + fd / bv1;
  printf("%.10f\n", secs);
  return 0;
}
