A simple puzzle game一个有趣的益智游戏

There are three suspects in the police station (Hu Tian, Wang Pangzi, Xiaojin), a police officer, one day, the police told three suspects to give you an opportunity to go out, the following is the police said the problem.
I have altogether 5 hats, of which there are 3 black hats and 2 gray hats. You stand in a row, the first day of Hu Wang Fat station second, station third small gold teeth, say the color of his own hat, guess the color of the hat in front of people under the condition of not, if there is a right that all can go out, small gold teeth did not know what color is your the hat, Wang Pangzi did not know the color of his own hat, then all the burden in Hu days on the body, so Hu days what colour is the hat?
在警察局中有三名嫌犯（胡天、王胖子、小金牙），一位警察，一天警察告诉三名嫌犯给你们一个出去的机会，以下是警察说的问题。
我一共有5顶帽子，其中有3顶黑色帽子、2顶灰色帽子。你们站成一列胡天站第一位、王胖子站第二位、小金牙站第三位， ，在不能说前方人帽子的颜色的情况下猜自己帽子的颜色，如果有一位猜对那就全部都可以出去，小金牙说不知道自己的帽子是什么颜色，王胖子也说不知道自己帽子是什么颜色，这时所有重担都在胡天身上，那么胡天帽子是什么颜色呢？