#include <bits/stdc++.h>
using namespace std;
void itval(istream_iterator<string> it) {}
template <typename T, typename... Args>
void itval(istream_iterator<string> it, T a, Args... args) {
  cerr << *it << " = " << a << endl;
  itval(++it, args...);
}
const long long int MOD = 1e9 + 7;
template <typename T>
inline void print(T x) {
  cout << x << "\n";
}
template <typename T>
inline void printvec(T x) {
  for (auto a : x) cout << a << ' ';
  cout << '\n';
}
struct custom {
  bool operator()(
      const pair<pair<long long int, long long int>, long long int> &p1,
      const pair<pair<long long int, long long int>, long long int> &p2) const {
    if (p1.first.first == p2.first.first) {
      return p1.first.second < p2.first.second;
    }
    return p1.first.first < p2.first.first;
  }
};
long long int get_pow(long long int a, long long int b) {
  long long int res = 1;
  while (b) {
    if (b & 1) res = (res * a) % MOD;
    a = (a * a) % MOD;
    b >>= 1;
  }
  return res;
}
const long long int N = 1e5 + 5, inf = 4e18;
long double dp[205][205][402];
void solve() {
  long long int n, l, k;
  cin >> n >> l >> k;
  std::vector<long double> v(n + 1);
  vector<int> a(n + 1);
  for (long long int i = (long long int)1; i < (long long int)(n + 1); i++) {
    cin >> v[i];
    v[i] /= 100.0;
  }
  for (long long int i = (long long int)1; i < (long long int)(n + 1); i++) {
    cin >> a[i];
    a[i]++;
  }
  dp[0][0][0] = 1.0;
  for (long long int i = (long long int)1; i < (long long int)(n + 1); i++) {
    for (long long int j = (long long int)0; j < (long long int)(i + 1); j++) {
      for (long long int z = (long long int)0; z < (long long int)(402); z++) {
        dp[i][j][z] += dp[i - 1][j][z] * (1 - v[i]);
        dp[i][j + 1][min(401ll, a[i] + z)] += dp[i - 1][j][z] * v[i];
      }
    }
  }
  long double ans = 0;
  for (long long int i = (long long int)l; i < (long long int)(n + 1); i++) {
    for (long long int z = (long long int)0; z < (long long int)(402); z++) {
      if (k + z - i >= 0) ans += dp[n][i][z];
    }
  }
  cout << fixed << setprecision(10) << ans;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int test = 1;
  clock_t z = clock();
  for (long long int tes = (long long int)0; tes < (long long int)(test);
       tes++) {
    solve();
  }
  fprintf(stderr, "Total Time:%.4f\n", (double)(clock() - z) / CLOCKS_PER_SEC),
      fflush(stderr);
  return 0;
}
