#include<cstdio>

#include<iostream>

#include<cstdlib>

#include<cstring>

#include<string>

#include<algorithm>

#include<map>

#include<queue>

#include<vector>

#include<cmath>

#include<utility>

using namespace std;

typedef long long LL;

const int N = 1008, INF = 0x3F3F3F3F;

#define MS(a, num) memset(a, num, sizeof(a))

#define PB(A) push_back(A)

#define FOR(i, n) for(int i = 0; i < n; i++)

int n, k;

double dis, v1, v2;

bool check(double m){

	double ti = 0;

	int tot = n / k;

	if(n % k){

		tot++;

	}

	for(int i = 0; i < tot; i++){

		double rem = dis - ti * v1;

		if(rem <= (m - ti) * v1){

			return true;

		}

		double len = v1 * (m - ti);

		double t2 = (rem - len) / (v2 - v1);

		ti += t2;

		if(i != tot - 1){

			double l2 = rem - len;

			ti += l2 / (v1 + v2);

		}

		if(ti > m){

			return false;

		}

	}

	return true;

}

int main(){

    cin>>n>>dis>>v1>>v2>>k;

    if(k >= n){

    	printf("%.10f\n", dis / v2);

    }else{

    	double l = dis / v2;

    	double r = dis / v1;

    	for(int i = 0; i < 100; i++){

    		double m = (l + r)/2;

    		if(check(m)){

    			r = m;

    		}else{

    			l = m;

    		}

    	}

    	printf("%.10f\n", l);

   	}

    return 0;

}