#include <bits/stdc++.h>
#pragma GCC optimize(2)
using namespace std;
int n, l, k, p[210], a[210];
double dp[2][210][210][210];
double pro[210];
signed main() {
  ios::sync_with_stdio(false);
  cin >> n >> l >> k;
  for (int i = 1; i <= n; i++) {
    cin >> p[i];
    pro[i] = p[i] * 1.0 / 100;
  }
  for (int i = 1; i <= n; i++) cin >> a[i];
  dp[0][0][0][k] = 1.0;
  for (int i = 1; i <= n; i++) {
    for (int j = 0; j <= i; j++) {
      for (int m = 0; m <= j; m++) {
        for (int l = k; l <= 200; l++) {
          if (a[i] == -1) {
            dp[i & 1][j][m][l] = 0.0;
            if (j > 0 && m > 0)
              dp[i & 1][j][m][l] += dp[(i - 1) & 1][j - 1][m - 1][l] * pro[i];
            dp[i & 1][j][m][l] += dp[(i - 1) & 1][j][m][l] * (1 - pro[i]);
          } else {
            dp[i & 1][j][m][l] = 0.0;
            if (j > 0 && l - a[i] >= k)
              dp[i & 1][j][m][l] +=
                  dp[(i - 1) & 1][j - 1][m][l - a[i]] * pro[i];
            dp[i & 1][j][m][l] += dp[(i - 1) & 1][j][m][l] * (1 - pro[i]);
          }
        }
        if (a[i] == -1) {
          dp[i & 1][j][m][201] = 0.0;
          if (j > 0 && m > 0)
            dp[i & 1][j][m][201] += dp[(i - 1) & 1][j - 1][m - 1][201] * pro[i];
          dp[i & 1][j][m][201] += dp[(i - 1) & 1][j][m][201] * (1 - pro[i]);
        } else {
          dp[i & 1][j][m][201] = 0.0;
          if (j > 0)
            dp[i & 1][j][m][201] += dp[(i - 1) & 1][j - 1][m][201] * pro[i];
          dp[i & 1][j][m][201] += dp[(i - 1) & 1][j][m][201] * (1 - pro[i]);
          if (j > 0) {
            for (int l = 200; l >= k; l--) {
              if (l + a[i] > 200) {
                dp[i & 1][j][m][201] += dp[(i - 1) & 1][j - 1][m][l] * pro[i];
              } else
                break;
            }
          }
        }
      }
    }
  }
  double ans = 0.0;
  for (int j = l; j <= n; j++) {
    for (int m = 0; m <= j; m++) {
      for (int l = k; l <= 201; l++)
        if (l >= m) {
          ans += dp[n & 1][j][m][l];
        }
    }
  }
  cout << fixed << setprecision(10) << ans << endl;
  return 0;
}
