Name: Amanda

Who is asking: Student
Level: Middle

To Whom It May Concern:

I have a brain teaser. My name is Amanda, and I am a student in the middle level category. Here's the question:

You have invited 11 people over to your house one day, and your friends are hungry. You go into the kitchen and find out you only have 1 donut (with a hole in the middle). In order to feed 12 people (including you), you must cut the donut into 12 pieces with only using a straight knife and cutting 3 times. This is NOT a trick question.



Hi Amanda,

I can help, provided that the pieces need not be of equal size.

It would not be possible to cut a muffin into 12 pieces with 3 straight cuts: The first cut would produce two pieces. Stacking these on top of each other (or in a line), it would be possible to split each of these in two with the second cut, resulting in 4 pieces. then putting all of these in a line and cutting through all of these with the last cut would result in 8 pieces, which is less than 12.

With a donut, the problem is resolved as follows: Cutting the O-shaped donut results in two C-shaped halves.

You stack these one atop the other and cut a straight line through the C shape to split each C shape into THREE pieces.

This gives you 6 donut pieces (though they may not all have the same weight). You then line these up on the table and cut horizontally through them all, and you get 12 pieces.

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