#include<bits/stdc++.h>
#define endl "\n"
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
//value 
struct ex{
	ll mo,da;
}ans[50005];
ll a[300005];

//function 
bool cmp(ex a,ex b){
	if(a.mo==b.mo)return a.da<b.da;
	return a.mo<b.mo;
}
void solve(){
	
	ll n,k;
	ll ma=-1,wz=-1;
	cin>>n>>k;
	for(ll i=0;i<n;i++)cin>>a[i];
	if(k==1){
		cout<<0<<endl;
		return;
	}
	ll tmp=0;
	ll q=k;
//	cout<<wz<<' '<<ma<<endl;
//	cout<<(ll)wz*ma+a[wz]<<endl;
	while(k<100000000000){
//		if(k==124)cout<<k<<endl;
		if(k<=10){
			k*=q;
			continue;
		}
		ll cnt=1;
		while(k/cnt>0)cnt*=10;
//		cnt/=10;
		for(ll i=1;i<cnt;i*=10){
			ll m=k/i,d=k%i;
			ll w=1;
			while(d/w>0)w*=10;
			if(m*w+d!=k)continue;
			if(m>n)continue;
			else if(d>a[m-1])continue;
			else{
				ans[tmp].mo=m;
				ans[tmp++].da=d;
			}
		}
		k*=q;
	}
	
	if(tmp==0){
		cout<<0<<endl;
		return;
	}
	sort(ans,ans+tmp,cmp);
	
	cout<<tmp<<endl;
	for(ll i=0;i<tmp;i++){
		cout<<ans[i].mo<<' '<<ans[i].da<<endl;
		ans[i].mo=0;
		ans[i].da=0;
	}
}
 
int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0); 
	
	int T;
	cin>>T;
	while(T--)solve();
	
	return 0;
}