#include<bits/stdc++.h>
using namespace std;
#define int long long
const int M=1e16+10;
 int a,b,c;
 int axx(int mad)
 {
 	int x=0,y=mad*60,ss=0;
 	while(y>=80)
 	{
	 int t=y/80;
	 y%=80;
	 x=x+t;
	 ss=ss+t;
	 y=y+((int)(ss/a))*b;
	 ss%=a;
	}
 	if(x<=c)return 0;
 	return 1;
 }
signed main()
{
  int t;
  cin>>t;
  while(t--)
  {
   cin>>a>>b>>c;
   int l=0,r=M;
   while(l<r)
   {
   	int mad=(l+r)/2;
   	if(axx(mad))r=mad;
   	else l=mad+1;
   }
   cout<<l<<'\n';
  }
}