#include <bits/stdc++.h>
using namespace std;
template <typename T, typename V>
ostream &operator<<(ostream &out, const pair<T, V> x) {
  out << "{" << x.first << " : " << x.second << "}";
  return out;
}
template <typename T>
ostream &operator<<(ostream &out, const set<T> x) {
  for (auto &it : x) {
    out << it << " ";
  }
  return out;
}
template <typename T>
ostream &operator<<(ostream &out, const multiset<T> x) {
  for (auto &it : x) {
    out << it << " ";
  }
  return out;
}
template <typename T, typename V>
ostream &operator<<(ostream &out, const map<T, V> x) {
  for (auto &it : x) {
    out << "[" << it.first << "]"
        << " = " << it.second << "\n";
  }
  return out;
}
template <typename T>
ostream &operator<<(ostream &out, const vector<T> x) {
  for (int i = 0; i < x.size() - 1; ++i) {
    out << x[i] << " ";
  }
  out << x.back();
  return out;
}
template <typename T>
ostream &operator<<(ostream &out, const vector<vector<T> > x) {
  for (int i = 0; i < x.size() - 1; ++i) {
    out << "[" << i << "]"
        << " = {" << x[i] << "}\n";
  }
  out << "[" << x.size() - 1 << "]"
      << " = {" << x.back() << "}\n";
  return out;
}
const int N = 1e6 + 5;
const int MOD = 1e9 + 7;
const int INF = 1e9;
long double p[N];
int a[N];
vector<pair<long long, long long> > x;
long double dp[205][205][205];
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n, l, k;
  cin >> n >> l >> k;
  x.resize(n);
  for (int i = 0; i < n; ++i) {
    cin >> x[i].second;
  }
  for (int i = 0; i < n; ++i) {
    cin >> x[i].first;
  }
  sort((x).rbegin(), (x).rend());
  for (int i = 1; i <= n; ++i) {
    p[i] = x[i - 1].second;
    p[i] = (p[i] / 100.0);
  }
  for (int i = 1; i <= n; ++i) {
    a[i] = x[i - 1].first;
  }
  dp[0][0][k] = 1.0;
  for (int i = 0; i <= n; ++i) {
    for (int j = 0; j <= l; ++j) {
      for (int sum = 0; sum < 205; ++sum) {
        dp[i + 1][j][sum] += dp[i][j][sum] * (1 - p[i + 1]);
        int nsum = sum;
        nsum += a[i + 1];
        if (nsum < 0) continue;
        nsum = min(nsum, 204);
        dp[i + 1][min(j + 1, l)][nsum] += dp[i][j][sum] * p[i + 1];
      }
    }
  }
  long double ans = 0;
  for (int sum = 0; sum < 205; ++sum) {
    ans += dp[n][l][sum];
  }
  cout.precision(10);
  cout << fixed << ans;
  return 0;
}
