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

#define int long long

#define rep(i,n) for(int i=0;i<(n);i++)
#define pb push_back
#define all(v) (v).begin(),(v).end()
#define fi first
#define se second
typedef vector<int>vint;
typedef pair<int,int>pint;
typedef vector<pint>vpint;

template<typename A,typename B>inline void chmin(A &a,B b){if(a>b)a=b;}
template<typename A,typename B>inline void chmax(A &a,B b){if(a<b)a=b;}

int N,M;
int A[22],P[22];

vector<int> fast_mobius_transform(vector<int> f) {
    for (int i = 0; (1 << i) < f.size(); i++) {
        for (int j = 0; j < f.size(); j++) {
            if (j & 1 << i) {
                f[j] -= f[j ^ 1 << i];
            }
        }
    }
    return f;
}
int gcd(int a,int b){
    return b?gcd(b,a%b):a;
}

signed main(){
    cin>>N>>M;
    rep(i,N)cin>>A[i];
    rep(i,N)cin>>P[i];

    vector<int>f(1<<N);
    f[0]=1;
    for(int i=1;i<1<<N;i++){
        int p=32-__builtin_clz(i)-1;
        int x=f[i^(1<<p)];
        int g=gcd(x,A[p]);
        if(1.0*x*A[p]/g>M)f[i]=M+1;
        else f[i]=x/g*A[p];
    }

    for(int i=0;i<1<<N;i++)f[i]=M/f[i];
    f[0]=0;
    vector<int>g=fast_mobius_transform(f);

    double ans=0.0;
    rep(i,1<<N){
        double q=1.0;
        rep(j,N){
            if(i>>j&1){
                q*=P[j]/100.0;
            }
            else{
                q*=(100-P[j])/100.0;
            }
        }
        ans+=q*abs(g[i]);
    }
    printf("%.20f\n",ans);
    return 0;
}