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.
Here we go:
- Fill the 6 cup pitcher with lemonade concentrate. This leaves 4 cups in the 10 cup pitcher.
- Empty the 6 cup pitcher into the 15 cup pitcher.
- Fill the 6 cup pitcher with water, and empty it into the 15 cup pitcher.
- (this may be cheating, but) Mark the 10 cup pitcher at the level of the lemonade concentrate (4 cups).
- Empty the the rest of the concentrate from the 10 cup pitcher into the 6 cup pitcher.
- Fill the 10 cup pitcher up to the 4 cup line you marked.
- Empty the 6 cup pitcher into the 10 cup pitcher, and voila. I count 8 discreet moves.
Edited on July 27, 2005, 11:34 pm