13 August 2018

The "potato paradox"

"You have 100 lb of potatoes, which are 99 percent water by weight. You let them dehydrate until they're 98 percent water. How much do they weigh now?

These are "mathematical" potatoes; you can substitute grapes or jellyfish or amoeba if you want something with a higher percentage of wet weight. 

But given the parameters of the question, what is the answer?

50 pounds.  This is a veridical paradox.

3 comments:

  1. What makes this problem statement most confusing is that it causes the brain to conflate pounds and percentages. It makes perfect sense after reading the wikipedia explanation. The one that still drives me nuts even after reading the proof is the Monty Hall Problem.

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  2. Outstanding. Just told my dad (95yo!) this at our weekly dinner - he was shocked. We've had similar discussions with the Monty Hall problem & .9999repeating=1. This one threw me for more of a loop than either of those =)

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  3. I saw this yesterday and thought "nope", only to come back to it today and solve it. Wow the years haven't made as dumb as I thought! Thanks! :D

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