Riddle: Mary was working in a chemistry lab with a mixture of chemicals that was 90% water and weighed 20 pounds. After returning to the lab from a weekend break, she calculated the mixture was now 50% water. How much does the mixture now weigh? For purposes of this puzzle, assume the non-water part of the mixture was not affected by evaporation.

12 Pounds

The Chemistry lab  Riddle Meme.
The Chemistry lab Riddle Meme.
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