#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int a[1000];

void solve() {
	ll a, b, c;
	cin >> a >> b >> c;

	ll mi = 1e18;
	for (int i = 0 ; i <= 31 ; i++) {
		ll x = 1LL << i;
		mi = min(mi, a * i + (c + x - 1) / x * b);
	}
	cout << mi << '\n';

}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	int t = 1;
	cin >> t;
	while (t--)
		solve();
	return 0;
}