#include <bits/stdc++.h>
using namespace std;
double n, l, v1, v2, k;
bool c(double x) {
  int num;
  if ((int)n % (int)k == 0)
    num = n / k;
  else
    num = n / k + 1;
  if (num * x + (num - 1) * x * (v2 - v1) / (v2 + v1) <= x + (l - x * v2) / v1)
    return 1;
  return 0;
}
int main() {
  scanf("%lf%lf%lf%lf%lf", &n, &l, &v1, &v2, &k);
  double lb = 0, rb = 1000000001;
  for (int i = 0; i < 100; i++) {
    double m = (lb + rb) / 2;
    if (c(m))
      lb = m;
    else
      rb = m;
  }
  printf("%lf", rb + (l - rb * v2) / v1);
  return 0;
}
