#include <bits/stdc++.h>
double mid;
long long n, l, v1, v2, k;
bool checkf(double t) {
  double timeOnBus = (l - v1 * t) / (v2 - v1);
  if (timeOnBus <= 0) return true;
  if ((l - v1 * t) / (v2 - v1) * ceil((double)n / k) +
          (ceil((double)n / k) - 1) * (l - v1 * t) / (v2 + v1) >
      t)
    return false;
  return true;
}
double bins(double beg, double en, int cnt) {
  while (beg <= en) {
    if (++cnt == 100) {
      return mid;
    }
    mid = beg + (en - beg) / 2;
    if (checkf(mid)) {
      en = mid;
    } else {
      beg = mid;
    }
  }
}
int main() {
  scanf("%I64d %I64d %I64d %I64d %I64d", &n, &l, &v1, &v2, &k);
  bins(0, 1000000000, 0);
  printf("%.7lf", mid);
  return 0;
}
