1, it takes 2 minutes to fry 1 No.2 cake and the front side for the first time. Take out No.2 cake for the second time, put No.3 cake, and fry the reverse side of 1 cake and the front side of No.3 cake for 2 minutes. At this time, 1 cake has been fried. Take out the 1 cake for the third time, and fry the reverse sides of the 2 nd and 3 rd cakes for 2 minutes. It takes six minutes in all. The point of this problem is to always keep two cakes frying in the pot at the same time, which is the most time-saving.

2. Consider two situations: (1) Weigh 3 bottles on each side for the first time. If it's the same weight, the heavy bottle must be in the remaining 2 bottles. Just weigh it again. It takes at least 2 times. (2) weigh 3 bottles on each side for the first time. If their weights are different, take two more bottles from the heavy end, and each side is called 1 bottle. If they weigh the same, the heavy bottle is the remaining bottle; If it is not the same weight, it is the sinking end. This also needs at least 2 times. The point of this problem is to divide the total into three parts, even if there is a remainder. This method is applicable to any total. ]