#include <bits/stdc++.h>
using namespace std;

template<class T>
bool chmax(T& a, const T& b) {
    if (a < b) { a = b; return true; }
    return false;
}
template<class T>
bool chmin(T& a, const T& b) {
    if (b < a) { a = b; return true; }
    return false;
}

// std::vector Declaration
template<typename T>
vector<T> make_v(size_t a) { return vector<T>(a); }
template<typename T, typename... Ts>
auto make_v(size_t a, Ts... ts) {
    return vector<decltype(make_v<T>(ts...))>(a, make_v<T>(ts...));
}

// std::vector Declaration and Initialization
template<typename T>
vector<T> make_vector(size_t a, T x) { return vector<T>(a, x); }
template<typename T, typename U, typename... Ts>
auto make_vector(size_t a, U b, Ts... ts) {
    return vector<decltype(make_vector<T>(b,ts...))>(a, make_vector<T>(b, ts...));
}

// std::vector Input
template<typename T>
istream& operator>>(istream& is, vector<T>& v) {
    for (auto &e : v) is >> e;
    return is;
}

// std::vector Debug
template<typename T>
ostream& operator<<(ostream& os, const vector<T>& v) {
    os << "[";
    bool a = 1;
    for (auto e : v) {
        os << (a ? "" : " ");
        os << e;
        a = 0;
    }
    os << "]";
    return os;
}

// std::array Debug
template<typename T, size_t n>
ostream& operator<<(ostream& os, const array<T, n>& v) {
    os << "[";
    bool a = 1;
    for (auto e : v) {
        os << (a ? "" : " ");
        os << e;
        a = 0;
    }
    os << "]";
    return os;
}

// std::deque Debug
template<typename T>
ostream& operator<<(ostream& os, const deque<T>& d) {
    os << "[";
    bool a = 1;
    for (auto e : d) {
        os << (a ? "" : " ");
        os << e;
        a = 0;
    }
    os << "]";
    return os;
}

// std::pair Debug
template<typename T, typename U>
ostream& operator<<(ostream& os, const pair<T, U>& p) {
    os << "(" << p.first << " " << p.second << ")";
    return os;
}

// std::set Debug
template<typename T>
ostream& operator<<(ostream& os, const set<T>& st) {
    os << "{";
    bool a = 1;
    for (auto e : st) {
        os << (a ? "" : " ");
        os << e;
        a = 0;
    }
    os << "}";
    return os;
}

// std::multiset Debug
template<typename T>
ostream& operator<<(ostream& os, const multiset<T>& st) {
    os << "{";
    bool a = 1;
    for (auto e : st) {
        os << (a ? "" : " ");
        os << e;
        a = 0;
    }
    os << "}";
    return os;
}

// std::map Debug
template<typename T, typename U>
ostream& operator<<(ostream& os, const map<T, U>& mp) {
    os << "{";
    bool a = 1;
    for (auto e : mp) {
        os << (a ? "" : " ");
        os << e.first << ":" << e.second;
        a = 0;
    }
    os << "}";
    return os;
}

// std::tuple Debug
template<int N, class Tuple>
void out(ostream& os, const Tuple& t){}
template<int N, class Tuple, class H, class ...Ts>
void out(ostream& os, const Tuple& t) {
    if (N) os << " ";
    os << get<N>(t);
    out<N+1,Tuple,Ts...>(os, t);
}
template<class ...Ts>
ostream& operator<<(ostream& os, const tuple<Ts...>& t) {
    os << "(";
    out<0,tuple<Ts...>,Ts...>(os, t);
    os << ")";
    return os;
}

// Debug
#define DUMP(x) cerr<<#x<<" = "<<(x)<<endl

// Weighted edge
template<typename T>
struct edge {
    int src, to;
    T cost;

    edge() {}
    edge(int to, T cost) : src(-1), to(to), cost(cost) {}
    edge(int src, int to, T cost) : src(src), to(to), cost(cost) {}

    friend ostream& operator<<(ostream& os, const edge& e) {
        return os << "(" << e.src << "->" << e.to << ":" << e.cost << ")";
    }
};

using LL = int64_t;

#define fs first
#define sc second

const int64_t MOD = 1e9+7;


template<typename T>
vector<T> fast_mobius_transform_2(const vector<T>& g) {
    // Return f(s):
    // s.t. g(s) = \sum_{t \subset s} f(t)
    // ( e.g. f(s) = \sum_{t \subset s} (-1)^|s-t| * g(t) )
    int n = g.size();
    vector<T> f = g;
    for (int i = 0; (1 << i) < n; ++i) {
        for (int j = 0; j < n; ++j) {
            if (j >> i & 1) {
                f[j] -= f[j & ~(1<<i)];
            }
        }
    }
    return f;
}


LL LCM(LL a, LL b) {
    return (LL)min(2e18l+10, a / __gcd(a, b) * 1.0l * b);
}

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);

    LL n, m; cin >> n >> m;
    vector<LL> a(n);
    vector<double> p(n);
    cin >> a >> p;

    for (int i = 0; i < n; ++i) {
        p[i] /= 100;
    }

    vector<LL> g(1<<n);

    for (int bit = 0; bit < 1<<n; ++bit) {
        LL lcm = 1;
        for (int i = 0; i < n; ++i) {
            if (bit >> i & 1) {
                lcm = LCM(lcm, a[i]);
            }
        }
        g[bit] = m / lcm;
    }

    auto f = fast_mobius_transform_2(g);

    double ans = 0;

    for (int bit = 0; bit < 1<<n; ++bit) {
        double prob = 1;
        for (int i = 0; i < n; ++i) {
            prob *= (bit >> i & 1 ? p[i] : 1 - p[i]);
        }

        ans += prob * (m - f[bit] * (__builtin_popcount(bit) & 1 ? -1 : 1));
    }


    cout << ans << endl;

    return 0;
}



Measured memory_bytes: 19376