#include <cstdio>
#include <algorithm>
#include <deque>
#define maxN 30500
#define INF (1<<20)
using namespace std;
int n, t[maxN], v[maxN], i, j, l, u, st, dr, mij;
long long s[maxN];
deque<long long> q;
bool deq(int x)
{
    int i;
    //sume partiale
    for(i = 1; i <= n; i++)
        s[i] = s[i-1] + v[i]*100-x*t[i];
    q.clear();
    //min_deque
    for(i = l; i <= n; i++)
    {
        while(!q.empty() && s[q.back()] >= s[i-l])
            q.pop_back();
        q.push_back(i-l);
        if(i-q.front() == u)
            q.pop_front();
        if(s[i]-s[q.front()] >= 0) return true;
    }
    return false;
}
int main()
{
    freopen("secv3.in", "r", stdin);
    freopen("secv3.out", "w", stdout);
    scanf("%d %d %d", &n, &l, &u);
    for(i = 1; i <= n; i++)
        scanf("%d", &v[i]);
    for(i = 1; i <= n; i++)
        scanf("%d", &t[i]);
    st=1, dr=INF;
    while(st <= dr)
    {
        mij = st+(dr-st)/2;
        if(deq(mij)) st = mij+1;
        else dr = mij-1;
    }
    printf("%.2lf", (double)(dr/100.0));
    return 0;
}