#include <bits/stdc++.h>
using namespace std;
int N, K;
double L, V1, V2;
bool moo(double tot) {
  double tbus = (L - V1 * tot) / (V2 - V1);
  double tinc = tbus + tbus * (V2 - V1) / (V1 + V2);
  return (N - 1) * tinc + tbus <= tot;
}
int main() {
  scanf("%d %lf %lf %lf %d", &N, &L, &V1, &V2, &K);
  N = (N + K - 1) / K;
  double lo = 0, hi = L / V1;
  for (int qq = 0; qq < 100; qq++) {
    double mid = (lo + hi) / 2;
    if (moo(mid)) {
      hi = mid;
    } else {
      lo = mid;
    }
  }
  printf("%.10lf\n", hi);
}
