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