#include <bits/stdc++.h>
#define int long long
#define lint long long
#define pii pair<int,int>
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(c) (c).begin(),(c).end()
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
#define MINF(a) memset(a,0x3f,sizeof(a))
#define POW(n) (1LL<<(n))
#define POPCNT(n) (__builtin_popcount(n))
#define IN(i,a,b) (a <= i && i <= b)
using namespace std;
template <typename T> inline bool CHMIN(T& a,T b) { if(a>b) { a=b; return 1; } return 0; }
template <typename T> inline bool CHMAX(T& a,T b) { if(a<b) { a=b; return 1; } return 0; }
template <typename T> inline void SORT(T& a) { sort(ALL(a)); }
template <typename T> inline void REV(T& a) { reverse(ALL(a)); }
template <typename T> inline void UNI(T& a) { sort(ALL(a)); a.erase(unique(ALL(a)),a.end()); }
template <typename T> inline T LB(vector<T>& v, T a) { return *lower_bound(ALL(v),a); }
template <typename T> inline int LBP(vector<T>& v, T a) { return lower_bound(ALL(v),a) - v.begin(); }
template <typename T> inline T UB(vector<T>& v, T a) { return *upper_bound(ALL(v),a); }
template <typename T> inline int UBP(vector<T>& v, T a) { return upper_bound(ALL(v),a) - v.begin(); }
template <typename T1, typename T2> ostream& operator<< (ostream& os, const pair<T1,T2>& p) { os << p.first << " " << p.second; return os; }
template <typename T1, typename T2> istream& operator>> (istream& is, pair<T1,T2>& p) { is >> p.first >> p.second; return is; }
template <typename T> ostream& operator<< (ostream& os, const vector<T>& v) { REP(i,v.size()) { if (i) os << " "; os << v[i]; } return os; }
template <typename T> istream& operator>> (istream& is, vector<T>& v) { for(T& in : v) is >> in; return is; }
template <typename T = int> 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...)); }
template <typename T, typename V> typename enable_if<is_class<T>::value == 0>::type fill_v(T &t, const V &v) { t = v; }
template <typename T, typename V> typename enable_if<is_class<T>::value != 0>::type fill_v(T &t, const V &v) { for(auto &e : t) fill_v(e,v); }
const lint MOD = 1000000007;
const lint INF = 0x3f3f3f3f3f3f3f3f;
const double EPS = 1e-10;

long long gcd(long long a, long long b) {
    while (b) {
        long long c = a % b;
        a = b;
        b = c;
    }
    return a;
}

const long long LIMIT = 1LL << 60;  // オーバーフローの閾値

long long mul(long long a, long long b) {
    if (a == LIMIT || b == LIMIT) return LIMIT;
    int res = 0;
    while (b > 0) {
        if (b & 1) res += a;
        if (res > LIMIT) return LIMIT;
        a += a;
        b >>= 1;
    }
    return res;
}

long long lcm_overflow(long long a, long long b) {
    if (a == LIMIT || b == LIMIT) return LIMIT;
    return mul(a / gcd(a, b), b);
}

int n, m;
int a[20], p[20];
int V[POW(20)];

void _main() {
    cin >> n >> m;
    REP(i, n) cin >> a[i];
    REP(i, n) cin >> p[i];
    FOR(bit, 1, POW(n)) {
        int mul = 1;
        REP(i, n) {
            if (bit >> i & 1)
                mul = lcm_overflow(mul, a[i]);
        }
        V[bit] = m / mul;
    }

    REP(i, n) REP(bit, POW(n)) {
        if (bit >> i & 1)
            V[bit] -= V[bit ^ (1 << i)];
    }
    long double ans = 0;
    REP(bit, POW(n)) {
        long double prob = 1.0;
        REP(i, n) {
            prob *= (bit >> i & 1 ? p[i] : 100 - p[i]) / 100.0;
        }
        ans += prob * abs(V[bit]);
    }
    cout << ans << endl;
}

signed main(signed argc, char **argv) {
    if (argc > 1) {
        if (strchr(argv[1], 'i'))
            freopen("input.txt", "r", stdin);
        if (strchr(argv[1], 'o'))
            freopen("output.txt", "w", stdout);
    }
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
    _main();
    return 0;
}


Measured memory_bytes: 11480