Fifteen Eighty Four

Academic perspectives from Cambridge University Press


Win a New Martin Gardner Book #2

Update: This is last week’s puzzle, click here for this week’s puzzle!

It’s that time again! I’ve got another problem from Martin Gardner’s Origami, Eleusis, and the Soma Cube, and another copy available to win. We’ll move on to the other of the two first volumes in a couple weeks. Find this week’s puzzle after the jump.

Thanks for all of your entries last week! The winner of the first puzzle, with a clever poem is Wei-Hwa Huang, a longtime Gardner fan. I had several other right answers, but let’s allow the poem to reveal what it is:

Suppose that the escalator connects floors 3 and 2,
and that more escalators connect the building through.

Let’s further add this additional supposition:
that when the Prof starts going up, he has some competition.

A humble janitor of the name Stanley Spadowski
starts at the same place and goes down at rate Slapenarski.

(And when we say “rate Slapenarski” we mean
that he goes down at the exact same rate we’ve seen.)

Finally, let’s say that Stanislaw tries to be extra manly:
he doesn’t stop climbing until floor 1 meets Stanley.

(Though these additions might seem rather deranged,
you have to admit that the floor height is unchanged.)

And now we ask for just one piece of datum:
Where is the prof when the custodian hits the bottom?

Well, we know that his speed is five times as shifty,
so when Stanley’s moved 50, Stanislaw’s moved 250.

At half of that Stanislaw had just reached floor three,
so he should be exactly on floor four, you see.

To sum up: the men are now separated by three floors,
have made in total 300 steps and no more.

A simple division means (unless we have blundered)
the height of one floor must be exactly… 100.

This week’s puzzle: The Flight Around the World

Read the rules here, same as last week, with the addition of “please get answers to me by the end of Tuesday (EST).” Who knows, if I’m running behind, I might let that one slip.

A group of airplanes is based on a small island. The tank of each plane holds just enough fuel to take it halfway around the world. Any desired amount of fuel can be transferred from the tank of one plane to the tank of another while the planes are in flight. The only source of fuel is on the island, and for the purposes of the problem it is assumed that there is no time lost in refueling either in the air or on the ground.

What is the smallest number of planes that will ensure the flight of one plane around the world in a great circle, assuming that the planes have the same constant ground speed and rate of fuel consumption and that all planes return safely to their island base?

Answer in the form below. Use “Gardner Week 2” in the subject line. If you wish to send an attachment, please email it to:

cupblog (dot) us (at) gmail (dot) com

All information will remain confidential.


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