Ambiguity often gives a certain piquancy — and humor, per Groucho Marx — to our lives. Cover up the text below this paragraph and let's start off with a puzzle: You're handed a balance and 27 identical coins, except one is a little lighter than the others. What's the fewest possible number of weighings you can make to determine which is the light coin?
If you said three, you got the "official" answer, i.e. to find the one light coin out of 27, weigh nine against nine. If they balance, the light one is in the remaining stack; if not, the light one is in the pile that goes up in the balance — either way, you've narrowed it down to one of nine. Of this group, weight three against three — now you're left with three coins, one of which is light. Weigh one against one and you've got it.
As I say, this is the official answer. But the question is ambiguous. Taking it literally: weigh 13 against 13, and if they balance, the light coin is the one not being weighed, that is, the fewest possible number of weighings is one.
For puzzle purists, this sort of ambiguity bedevils not only logic puzzles but puzzles of all types. F'rinstance, I recently saw this in an IQ test: "Cow, pig, hen, sheep. Which is the odd one?" The "official" answer is, of course, hen, the only bird (or the only one without four legs.) But equally:
Cow = only one with letters alphabetically arranged
Pig = only one with non-kosher meat
Sheep = only one not having three letters
That is, "all of the above" is correct.
"The only mammals native to Australia are marsupials." True or false? If you said "true," you fell for the ambiguity of the question and forgot about (non-marsupial) humans, namely Australian aborigines.
Ambiguous headlines are sometimes referred to as "crash blossoms" after a headline in Japan Today newspaper: "Violinist Linked to JAL Crash Blossoms." The story was about the daughter of a Japan Airlines crash victim having a successful symphony career. Legendary (but true) crash blossoms include:
Red Tape Holds up New Bridge
Eighth Army Push Bottles up Germans
Giant Waves Down Queen Mary's Funnel
And this from the Associated Press (right out of Monty Python): McDonald's Fries the Holy Grail for Potato Farmers.
Finally, as immortalized in Time magazine, an editor sent a telegram to Cary Grant's agent (you paid by the word in those days): "HOW OLD CARY GRANT?" Grant, who happened to be there, replied, "CARY GRANT FINE HOW YOU?"
Barry Evans (firstname.lastname@example.org) is so happy to have his new 96-column anthology, Revenge of Field Notes available at local bookstores.