#include <bits/stdc++.h>
int main() {
  int n, l, v1, v2, k;
  while (~scanf("%d%d%d%d%d", &n, &l, &v1, &v2, &k)) {
    if (k >= n) {
      printf("%.10lf\n", l * 1.0 / v2);
      continue;
    }
    int t = (n - 1) / k;
    double s = v2 * 1.0 / v1;
    double kk = (1 + s) / (3 + s);
    double temp = kk + t * (1 - kk);
    temp = l * 1.0 / (temp * v1);
    printf("%.10lf\n", temp * (kk / s + t * (1 - kk)));
  }
  return 0;
}
