#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, l, k;
  cin >> n >> l >> k;
  vector<int> a(n), p(n);
  for (int i = 0; i < n; i++) cin >> p[i];
  for (int i = 0; i < n; i++) cin >> a[i];
  vector<vector<double> > dp(n + 1, vector<double>(2 * n + 1, 0.0));
  dp[0][n + min(n, k)] = 1.0;
  for (int i = 0; i < n; i++) {
    vector<vector<double> > dp2(n + 1, vector<double>(2 * n + 1, 0.0));
    double w = p[i] / 100.0;
    for (int j = 0; j < dp.size(); j++) {
      for (int m = 0; m < dp[j].size(); m++) {
        if (a[i] < 0) {
          if (m && j + 1 < dp2.size()) dp2[j + 1][m - 1] += dp[j][m] * w;
          dp2[j][m] += dp[j][m] * (1.0 - w);
        } else {
          if (j + 1 < dp2.size())
            dp2[j + 1][min(2 * n, m + a[i])] += dp[j][m] * w;
          dp2[j][m] += dp[j][m] * (1.0 - w);
        }
      }
    }
    swap(dp, dp2);
  }
  double ans = 0.0;
  for (size_t i = l; i < dp.size(); i++) {
    for (size_t j = n; j < dp[i].size(); j++) {
      ans += dp[i][j];
    }
  }
  cout << ans << endl;
  return 0;
}
