Cool concept. Took me a minute to think it through before I could make sense of it.
I think it is the fact that they used potatoes that makes it counterintuitive. Had it instead been a glass of water that had 1% of dissolved salt in it, it would have been very straightforward.
I think it is the fact that they used potatoes that makes it counterintuitive. Had it instead been a glass of water that had 1% of dissolved salt in it, it would have been very straightforward.