#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define MID int mid=(l+r)>>1;
#define ls p<<1
#define rs p<<1|1
int n,a,b,c;
int main(){
	int T;
	cin>>T;
	while(T--){
		cin>>a>>b>>c;
		ll ans=0x3f3f3f3f3f3f3f3f;
		for(int i=0;i<=30;i++){
			int n=1<<i;
			ll res=1ll*a*i;
			res+=1ll*((c-1)/n+1)*b;
			ans=min(ans,res);
		}
		cout<<ans<<endl;
	}
}