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Camel Crossing the Desert Puzzle

One of the most memorable problems I got to work through at the OGAP (Oklahoma Geometry and Algebra Project) workshop I attended was the Camel Crossing the Desert Puzzle.

Camel walking next to bunch of bananas

A week before attending the workshop, I had saw the problem in a copy of Discovering Advanced Algebra. I read the problem, and I thought it sounded interesting. But, I didn’t really take any time to solve it.

camel clipart
Clipart from ClipArt ETC – one of the best sources for free clipart for the classroom!

The version we attempted reads as follows:

A camel is sitting by a stack of 3000 bananas at the edge of a 1000 mile-wide desert.  He is going to travel across the desert, carrying as many bananas as he can to the other side.  He can carry up to 1000 bananas at any given time, but he eats one banana at every mile.  What is the maximum number of bananas the camel can transport across the desert?  How does he do it?  Be prepared to present your solution to the class.  (Hint: the camel doesn’t have to go all the way across the desert in one trip.)

My group got right to work and figured out a way to transport 500 bananas across the desert on our first try.  Linda, one of the facilitators, looked at our solution and told us that we could do better than that.  We tried, but every subsequent strategy ended up transporting less than 500 bananas!  

One group was able to arrive at the solution during the 45 or so minutes we were given to work on the problem.  The rest of us had to take the problem home for homework.  At home, I tried to solve the problem by employing simpler cases.  But, I never did make the breakthrough I needed.

The next day, they provided us the solution.  I kinda wish I had left the room during the explanation so I could have figured it out for myself.  Oh well…  There are plenty of other math problems out there for me to solve!

Fawn Nguyen gives her students a version of this problem that involves transporting 45 watermelons across a 15 kilometer desert.  I think this problem would be much more approachable for my students.  Plus, you can easily represent 45 watermelons with manipulatives.  I wouldn’t want to try to represent 3000 bananas!  I definitely want to work this problem into my curriculum next year!

I think it would make a great task to give students at either the beginning or end of the school year!

Puzzle Solutions

I intentionally do not share solutions to the puzzles I feature on my website because I strive to provide learning experiences for my students that are not google-able. I would like other teachers to be able to use these puzzles in their classrooms as well without the solutions being easily found on the Internet.

However, I do recognize that us teachers are busy people and sometimes need to quickly reference an answer key to see if a student has solved a puzzle correctly or to see if they have interpreted the instructions properly.

If you are a teacher who is using these puzzles in your classroom, please send me an email at sarah@mathequalslove.net with information about what you teach and where you teach. I will be happy to forward an answer key to you.

Esther Vargas

Sunday 8th of November 2015

So many great resources! Thank you for sharing!

Sarah Carter (@mathequalslove)

Monday 9th of November 2015

You are very welcome!

PEMom

Thursday 26th of June 2014

I teach junior high and we were fortunate enough to adopt the middle school edition of Big Ideas Math. I used it this past year and really enjoyed it. Thanks for sharing your experiences at the conference. I use it as my professional development since we are pretty limited right now in our district. :)

Sarah Carter (@mathequalslove)

Friday 27th of June 2014

Glad I could help you in this way! My district provides very limited pd also. Luckily, there are several groups who offer amazing free pd in my area of the state.

Room110

Thursday 26th of June 2014

Wow great post! Thanks for sharing all the ideas. Even though I am overwhelmed with the information, I can't wait to read your next post! :-)

Sarah Carter (@mathequalslove)

Friday 27th of June 2014

Thanks! Glad you're enjoying my recaps!

Jan Lichtenberger

Thursday 26th of June 2014

Sarah, oh my, I absolutely love the contrasting cases! I am putting everything down this minute so I can spend time looking through these. What a find! Thank you so much for sharing.

Sarah Carter (@mathequalslove)

Friday 27th of June 2014

I got so, so excited when the presenter showed us this amazing resource. Glad someone else is as excited about it as me!

Melissa

Wednesday 25th of June 2014

Ok I am getting so jealous of all the opportunities that you have for PD!!!

Sarah Carter (@mathequalslove)

Friday 27th of June 2014

:) This has been an amazing summer for PD! And, I haven't even got to experience Twitter Math Camp yet.