You have 3 unmarked pitchers that hold 6 cups, 10 cups, and 15 cups. The 10 cup pitcher is filled with lemonade, but you have to dilute it so people at the party don't complain that it's too sour. Unfortunately, I have, in the name of logic, broken your only measuring cup.

How can you dilute the lemonade to 20 cups such that all of the lemonade is of equal concentration? You have a sink with unlimited water, but you can't waste any lemonade. Try using as few moves as possible.

Pour half of the lemonade into the 15 C. pitcher and the other half in the 6C. pitcher.
Fill the 10 C. pitcher with water, then pour half of the water into the 15 C. pitcher(giving you 10 c. of properly mixed lemonade).
Pour the lemonade from the 6 C. pitcher into the 10 C. pitcher and you have another pitcher of properly diluted lemonade. 20 cups total. 

Posted by Shelagh on 2005-08-10 17:20:19