#include <bits/stdc++.h>

using namespace std;

long long query(int a, int b, int c, int l)
{
    auto value = [&](int v) {
        return 1LL * v * a + 1LL * (c + v - 1) / v * b;
    };

    int s = 1, e = l;
    while (s < e) {
        int mid = (s + e) / 2;
        if (value(mid) < value(mid + 1)) {
            e = mid;
        } else {
            s = mid + 1;
        }
    }

    return value(s);
}

void solve()
{
    int a, b, c;
    scanf("%d %d %d", &a, &b, &c);

    long long ans = 1LL << 60;
    for (int p = 0; p <= 30; ++p) {
        int temp = 1 << p;
        long long cand = 1LL * a * p + 1LL * (c + temp - 1) / temp * b;
        ans = min(ans, cand);
    }

    printf("%lld\n", ans);
}

int main()
{
    int cases;
    scanf("%d", &cases);

    while (cases--) {
        solve();
    }

    return 0;
}