#include <bits/stdc++.h>
using namespace std;

const int N = 210;
int n, l, K, a[N];
long double p[N], f[N][N][N << 1];
int main() {
    cin >> n >> l >> K;
    for (int i = 1; i <= n; i++) {
        cin >> p[i];
        p[i] = p[i] / 100.0;
    }
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
    }
    K = min(n, K);
    long double ans = 0;
    f[0][0][K + n] = 1;
    for (int i = 1; i <= n; i++) {
        for (int j = 0; j <= i; j++) {
            for (int k = 0; k <= n * 2; k++) {
                f[i][j][min(2 * n, k + a[i])] = f[i - 1][j][min(2 * n, k + a[i])] * (1 - p[i]);
                if (j) {
                    f[i][j][min(2 * n, k + a[i])] += f[i - 1][j - 1][k] * p[i];
                }
            }
        }
    }
    for (int i = l; i <= n; i++)
        for (int j = n; j <= 2 * n; j++) ans += f[n][i][j];

    printf("%.6llf", ans);

    return 0;
}