Pragmatic tools and ideas for the classroom

Numeracy Task 1 – The Glass Orb Drop


'Sphere_2720' by doviendeYou have two glass orbs of equal strength and a 40 story building.
Your task is to determine the highest floor from which you can drop an orb without it breaking.
What is the least number of drops required to do this?
Both orbs may be broken in order to determine your answer.
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You can find out more about Numeracy Tasks in my ‘Pair-a-Dimes’ blog.
I will tag all tasks like this with Numeracy so that they are easy to find in one location.

Please feel free to post your questions or best answer in a comment… but do not ruin the challenge for others by explaining how you got to that answer here! If you feel compelled to share your method, please do so by contacting me. Thanks!

Image: ‘Sphere_2720’by doviende


January 27, 2007 - Posted by | contact, David Truss, lessons, Math, Numeracy, Pair-a-Dimes

1 Comment

  1. Heeello! : ) I found this image on google images and was wondering if I could use it for a website header.

    If it is yours, I promise it’s only a temporary image, and will be replaced with another quite soon.

    And if it doesn’t belong to you, then do you know who’s it is?~

    Comment by Stripey | August 3, 2008

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