#include <bits/stdc++.h>
using namespace std;
double dp[205][405][205];
double p[1234];
int a[12345];
int main() {
  std::ios::sync_with_stdio(false);
  int n, l, k, i, j, r;
  cin >> n >> l >> k;
  for (i = 1; i < n + 1; i++) {
    cin >> p[i];
    p[i] /= 100.00;
  }
  for (i = 1; i < n + 1; i++) {
    cin >> a[i];
  }
  dp[0][201 + k][0] = 1;
  for (i = 0; i < n; i++) {
    for (j = 0; j < 404; j++) {
      for (r = 0; r < n + 1; r++) {
        if (!dp[i][j][r]) continue;
        if (a[i + 1] != -1) {
          dp[i + 1][min(j + a[i + 1], 403)][r + 1] += dp[i][j][r] * p[i + 1];
        } else {
          dp[i + 1][j - 1][r + 1] += dp[i][j][r] * p[i + 1];
        }
        dp[i + 1][j][r] += dp[i][j][r] * (1 - p[i + 1]);
      }
    }
  }
  double sumi = 0;
  for (j = 201; j < 404; j++) {
    for (r = l; r < n + 1; r++) {
      if (dp[n][j][r]) sumi += dp[n][j][r];
    }
  }
  cout << setprecision(20) << sumi << endl;
}
