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.

(In reply to Solution, but not necessarily minimal by Paul)

Wow, so elegant compared to mine! I see one way to make the ending steps a bit less work.

From this point:

Fill the "6" from the "15" -- you now have ....  and an empty "10"

...if you do the final dilution using the contents of the 15-c pitcher first you reduce the transferring by one pouring. Great job.

Posted by gail on 2005-07-26 06:31:18