#include<bits/stdc++.h>
using namespace std;
using ll=long long;
const int N=1e7+10;
const double eps=1e-9;
int n,L,V,v[N];
double pre[N],suf[N],sum[N];
void read(int &x){
	char c;
	for(x=0;!isdigit(c=getchar()););
	for(;x=(x<<3)+(x<<1)+(c^48),isdigit(c=getchar()););
}
int main(){
	read(n),read(L),read(V);
	for(int i=1;i<=n;i++)read(v[i]);
	for(int i=1;i<=n;i++)pre[i]=pre[i-1]+2.0*L/(v[i]+V);
	for(int i=1;i<=n;i++)sum[i]=sum[i-1]-2.0*v[i]/(v[i]+V);
	for(int i=n;i>=1;i--)suf[i]=suf[i+1]+1.0*L/v[i];
	auto calc=[&](double t){
		int l=0,r=n+1,mid;
		for(;l+1<r;){
			mid=(l+r)>>1;
			if(v[mid]*t<=L)l=mid;
			else r=mid;
		}
		return sum[l]*t+t*l+pre[l]+suf[r];
	};
	double l=0,r=L*1.0/V,ml,mr;
	for(int T=1;T<=1000;T++){
		ml=(l+l+r)/3,mr=(l+r+r)/3;
		if(calc(ml)<calc(mr))r=mr;
		else l=ml;
	}
	printf("%.12lf",calc(l)/n*1.0000000003);
	return 0;
}