In can ping one computer, but it can't ping back.?

I have no idea why they cant ping each other, except they may be using the same router. But I didn't test my many minecraft servers like that, I got someone else to see if they could connect to it (note both computers must be in the same network and have hamachi running). Get someone you know to test their connection on that IP, make sure your not tunneling the server and your IP is set to the hosts hamachi IP. ##.###.###.##:##### They must enter the port. And make sure you can connect aswell. That's all I got.