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
No Subject by Shelagh)
Is this different from what is already posted? And by the by, using a pen is cheating (but creative!)
1) Pour all of #10 into #15
2) Fill up #10 with water
3) Fill the #6 completely from the #10
4) Dump the #6
5) Fill the #6 from the #15
6) Pour the four cups of concentrate left in the #15 into the 4 cups water in the #10
7) Pour the 6 cups of lemon from the #6 into the #15
8) Fill the #6 with water
9) Pour the six cups of water from the #6 into the 6 cups of concentrate in the #15