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

#define FOR(i, m, n) for(int (i) = (m); (i) < (n); (i)++)
#define rep(i, n) FOR(i, 0, n)
#define co(n) cout << (n) << endl
#define cosp(n) cout << (n) << ' '
#define all(s) (s).begin(), (s).end()
#define pb push_back
#define mp make_pair
#define fs first
#define sc second
typedef long long ll;
typedef pair<int, int> P;

const ll INF = 1e9+1;
const ll LINF = 1e18+1;
const ll MOD = 1e9+7;
//const ll MOD = 998244353;

ll query(int a, int b, int c){
	if(c == 1) return -1;
	ll ans = 0;
	while(a){
		if(a < c){
			ans += b;
			a = 0;
		}else if(a < 2*c-1){
			ans += b;
			a -= c-1;
		}else if(a%c){
			ans += b;
			a -= a%c;
		}else{
			ans += b;
			a /= c;
		}
	}

	return ans;
}

int main(void){
	int q;
	cin >> q;

	rep(i, q){
		int a, b, c;
		cin >> a >> b >> c;
		co(query(a, b, c));
	}

	return 0;
}