#include <bits/stdc++.h>
int main(int argc, char const *argv[]) {
  int n, l, v1, v2, k;
  scanf("%d%d%d%d%d", &n, &l, &v1, &v2, &k);
  if (k >= n) {
    printf("%.10f\n", l * 1.0 / v2);
    return 0;
  } else {
    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("%.10f\n", temp * (kk / s + t * (1 - kk)));
  }
  return 0;
}
