#include <iostream>
#include <fstream>
#include <iomanip>

using namespace std;
ifstream f("secv3.in");
ofstream g("secv3.out");
float c[30010];
int main()
{
    float s1=0,s2=0,numar;
    double x=-9999999999999;
    int d,z,p=1;
    float a[30010],b[30010];
    int n,l,u;
    f>>n>>l>>u;
    for(int i=1;i<=n;i++)
    {
        f>>a[i];
    }
    for(int i=1;i<=n;i++)
    {
        f>>b[i];
        c[i]=a[i]/b[i];
    }
    for(int i=1;i<=n;i++)
        if(x<c[i]){x=c[i];d=i;}
    z=d;
    while(u>p)
    {
        if(d+1<=n&&c[d+1]>1)
            if(p+1<=u){p++;d++;}
        if(z-1>0&&c[z-1]>1)
            if(p+1<=u){p++;z--;}
        if(l>p)
        {
            if(c[d+1]>c[z-1]){d++;p++;}
            else{z--;p++;}
        }
        if(l<=p&&c[d+1]<1&&c[z-1]<1)break;
    }
    for(int i=z;i<=d;i++)
    {
        s1+=a[i];
        s2+=b[i];
    }
    numar=s1/s2;
    g<<fixed<<setprecision(2)<<numar;
    return 0;
}