From wiki - Fred brings home $100$ kg of potatoes, which (being purely mathematical potatoes) consist of $99\%$ water. He then leaves them outside overnight so that they consist of $98\%$ water. What is their new weight? The surprising answer is $50$ kg.
When I look at the problem, I assume that $99\%$ water is equal to $99$ kg and the rest is $1$ kg. When the percentage of the water is now $98\%$ the weight is now $98$ kg and the rest is $2$ kg.
I don't understand how the total weight can be $50$ kg at the end, maybe the water turns into a solid?