using System;
using System.Linq;
using System.Collections.Generic;
using Debug = System.Diagnostics.Debug;
using SB = System.Text.StringBuilder;
//using System.Numerics;
//using static System.Math;
using System.IO;
using Number = System.Int64;
namespace Program {
    public class Solver {

        public void Solve() {
            var n = ri;
            var m = rl;
            var a = Enumerate(n, x => rl);
            var p = Enumerate(n, x => ri / 100.0);
            var dp = new long[1 << n];
            var ep = new double[1 << n];
            for (int i = 1; i < 1 << n; i++) {
                long x = 1;
                double q = 1;
                for (int j = 0; j < n; j++)
                    if ((i >> j & 1) == 1) {
                        var gcd = MathEx.GCD(x, a[j]);
                        x /= gcd;
                        if (1.0 * x * a[j] > m) x = m + 1;
                        else x *= a[j];
                        q *= p[j];
                    }
                    else q *= 1 - p[j];
                dp[i] = m / x;
                ep[i] = q;
            }
            for (int i = 0; i < n; i++)
                for (int j = 0; j < 1 << n; j++)
                    if ((j >> i & 1) == 1) dp[j] -= dp[j ^ (1 << i)];
            var sum = 0.0;
            for (int i = 0; i < 1 << n; i++)
                sum += ep[i] * Math.Abs(dp[i]);
            Console.WriteLine("{0:0.000000000}", sum);
        }



        const long INF = 1L << 60;
        //int[] dx = { -1, 0, 1, 0 };
        //int[] dy = { 0, 1, 0, -1 };
        //*
        int ri { get { return sc.Integer(); } }
        long rl { get { return sc.Long(); } }
        double rd { get { return sc.Double(); } }
        string rs { get { return sc.Scan(); } }
        //*/

        public IO.StreamScanner sc = new IO.StreamScanner(Console.OpenStandardInput());
        static T[] Enumerate<T>(int n, Func<int, T> f) { var a = new T[n]; for (int i = 0; i < n; ++i) a[i] = f(i); return a; }
        static public void Swap<T>(ref T a, ref T b) { var tmp = a; a = b; b = tmp; }
    }
}

#region main
static class Ex {
    static public string AsString(this IEnumerable<char> ie) { return new string(ie.ToArray()); }
    static public string AsJoinedString<T>(this IEnumerable<T> ie, string st = " ") {
        return string.Join(st, ie.Select(x => x.ToString()).ToArray());
        //return string.Join(st, ie);
    }
    static public void Main() {
        Console.SetOut(new System.IO.StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false });
        var solver = new Program.Solver();
        solver.Solve();
        Console.Out.Flush();
    }
}
#endregion
#region Ex
namespace Program.IO {
    using System.IO;
    using System.Text;
    using System.Globalization;
    public class Printer: StreamWriter {
        public override IFormatProvider FormatProvider { get { return CultureInfo.InvariantCulture; } }
        public Printer(Stream stream) : base(stream, new UTF8Encoding(false, true)) { }
    }
    public class StreamScanner {
        public StreamScanner(Stream stream) { str = stream; }
        public readonly Stream str;
        private readonly byte[] buf = new byte[1024];
        private int len, ptr;
        public bool isEof = false;
        public bool IsEndOfStream { get { return isEof; } }
        private byte read() {
            if (isEof) return 0;
            if (ptr >= len) { ptr = 0; if ((len = str.Read(buf, 0, 1024)) <= 0) { isEof = true; return 0; } }
            return buf[ptr++];
        }
        public char Char() { byte b = 0; do b = read(); while ((b < 33 || 126 < b) && !isEof); return (char)b; }

        public string Scan() {
            var sb = new StringBuilder();
            for (var b = Char(); b >= 33 && b <= 126; b = (char)read())
                sb.Append(b);
            return sb.ToString();
        }
        public string ScanLine() {
            var sb = new StringBuilder();
            for (var b = Char(); b != '\n' && b != 0; b = (char)read())
                if (b != '\r') sb.Append(b);
            return sb.ToString();
        }
        public long Long() { return isEof ? long.MinValue : long.Parse(Scan()); }
        public int Integer() { return isEof ? int.MinValue : int.Parse(Scan()); }
        public double Double() { return isEof ? double.NaN : double.Parse(Scan(), CultureInfo.InvariantCulture); }
    }
}
#endregion
#region gcd,lcm
static public partial class MathEx {
    static public int GCD(int n, int m) { return (int)GCD((long)n, m); }
    static public long GCD(long n, long m) {
        n = Math.Abs(n); m = Math.Abs(m);
        while (n != 0) {
            m %= n;
            if (m == 0) return n;
            n %= m;
        }
        return m;
    }
    static public long LCM(long n, long m) { return (n / GCD(n, m)) * m; }
    static public long GCD(params long[] a) {
        var gcd = a[0];
        foreach (var x in a)
            gcd = GCD(gcd, x);
        return gcd;
    }

}
#endregion


Measured memory_bytes: 25984