#include <iostream>

using ll = long long;
using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int t;
    cin >> t;
    while (t--) {
        ll a, b, c;
        cin >> a >> b >> c;
        auto t = [&](auto &&t, ll n) -> ll {
            return n == 1 ? b : min(n * b, t(t, (n + 1) / 2) + a);
        };
        cout << t(t, c) << endl;
    }

    return 0;
}