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Mathematical pizza party

By David, 6 March 2019 Brainteaser

Four mathematicians – Annie, Beth, Carol and Donna – have a fun tradition. Every Friday, they order a pizza. But before they can eat, they must each solve a puzzle.

There’s one more strange thing about these mathematicians. It takes each of them exactly one minute to eat a slice of pizza.

This Friday, Annie was the first to finish the puzzle. She opened the pizza box, noticed there were eight slices and started eating.

One minute later, Beth finished the puzzle and started eating pizza. Another minute later, and Carol had finished too. Finally, Donna took one more minute before she solved the puzzle.

Of course, when Donna was just about to grab a slice of pizza, she realised there weren’t enough pieces to go around. Luckily, she had brought a pizza cutter.

How many cuts did she need to make to share the rest of the pizza evenly?

Scroll down for the answer!

 

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Brainteaser answer

First, we can count the pieces that were eaten before Donna finished the puzzle. Annie ate three slices, Beth ate two and Carol had one. So six of the eight slices were already eaten, leaving two slices.

To share the remaining pizza, each slice needs to be cut in two. That should take two cuts, but there’s a trick… if you put the two pieces point to point , you can cut both of them in half with just one cut!

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