Reinman’s Riddle


Imagine a rope that surrounds the equator, precisely. An exact snug fit. Now add 60 feet to the length of the rope.

There will now be space between the surface of the earth and the rope.

How much slack will you get? How far off the surface of the earth will the rope now stand?

a) 60 feet

b) 10 feet

c) 1 inch

d) .oo2 millimeters

Use the comment section to tell us what you think.


10 Responses to Riddle

  1. Dina says:

    Okay, where are you going with this?

  2. The point is – you don’t always get what you think you got. “intuition” could be way off.

  3. LarryB says:

    Who cares?

  4. Fred says:

    Thinking D, although math was never my strong subject.

  5. adi1957 says:

    My, my, I never thought that I would see this riddle on this site! I have seen this many times over all my years – and like most I don’t really know the answer to this riddle, but I reckon it is 1in.

  6. Fred says:

    10 feet; as the perimeter divided by 3,14 is the diameter, and then take half of it.

    • A snug fit would imply the rope sitting on the ground down the valleys and over the hills touching the ground every inch of the way. If you add 60 feet then there would be 60 ft of slack. The distance from the ground I would presume is unknowable with out knowing the precise length of the rope. But you could always guess.

I would like to thank all of you who took a shot at answering this riddle, and congrats to Fred for getting the correct answer. The reason I posted this little diversion is because it demonstrates an important truth.

At first glance most of would think that the answer to this riddle cannot be “10 feet”, but it is. This demonstrates that our confidence in our understanding of reality is no gauge of accuracy. If we want to be honest with ourselves we can never shut our minds, but instead we should always keep our minds open to correction.

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4 Responses to Reinman’s Riddle

  1. glarrybarryB says:

    I accept defeat but you asked two questions and Fred only gave one answer.

  2. Doovid says:

    You say try again? can’t……it has given me a splitting headache

  3. remi4321 says:

    “If we want to be honest with ourselves we can never shut our minds, but instead we should always keep our minds open to correction.”

    In a way I agree with you. I was reading about creative thinking and how to improve processes in a company in a management book and a quote structured me

    “We learn to accept what we learn instead of challenging it.”

    As an ex-christian, I came to the conclusion that Jesus is not the messiah. But in a way, we all believe we are right. Have you, as a rabbi studied and check with an open heart about Christianity? I honestly tried my best to seek the truth and I came to the conclusion that Jesus could not be the messiah.

    I guess that it is human nature, we are stuck on the left side of our brain and don’t want to challenge what we believe. It is easier for us and easier to accept our truth than accepting we could be wrong.

    But where does it stop? I mean, a Muslim could ask me to believe in his book. And obviously, I won’t read the quran (and I am not interested to do thata) or all the religious book there is to try to find the truth. I honestly believe that Judaism makes sense, and I am not looking to change. But again, this is a bias way of thinking.

    Maybe we are all seeking a truth that fits our need in the end. Maybe it is easier for you, a Jew. The Bible warns against looking for other gods. As for me, I will stay where I am anyway and believe the Hewbrew Bible as it is the only thing that make sense to me.

    Have you ever listened to debates, what struck me is that none of the parties listen to the other argument, but to counter-argument it. If only religion would be as easy as maths… We could all find the answer and the answer would always be 100% accurate. For Spiritual truth though, it’s no help we are all in the same boat. I think all seek to find the truth and some look in the wrong direction. Hopefully I am not one of them

    Cheers and Shabbat Shalom

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