Name:Amanda
Who is asking: Student
Level:Middle
Question:
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.
Sincerely,
Amanda
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 bepossible to split each of these in two with the second cut, resulting in 4 pieces. then putting all of these in a lineand cutting through all of these with the last cut would resultin 8 pieces, which is less than 12.
With a donut, the problem is resolved as follows: Cuttingthe O-shaped donut results in two C-shaped halves.
You stackthese one atop the other and cut a straight line through the C shapeto split each C shape into THREE pieces.
This gives you 6 donut pieces (though theymay not all have the same weight). You then line these up on the table andcut horizontally through them all, and you get 12 pieces. Cheers,
Claude
