No doubt here, people: I'm not food savvy, could never be a gourmet. Give me bread in my cupboard and steak on my plate! Sushi sets me on edge - it's fish bait! Broil me two salmon instead. Indict me if you will for a recent faux pas. At the Indonesian restaurant I coughed up my rijstafel and sent a debris of rice to the floor. Aye, and you know they run a tight ship there! For all I've been through, I'd write me a column - but I'm not great with words, either. I'm rescued often by mnemonic aids for Worsecter, halfpenny, rendezvous and others. But one task I've almost completed: I'll finish it now.
Question: Why is it so noisy at Wimbledon? Answer: you can't play there without raising a racquet!
Now ... what have I done? i.e. what is special about the paragraph above?
Jkyle1980's solution is correct, and much less verbose than what follows.
You can distinguish among 3**N cases in N weighings.
There are 54 possible cases in this puzzle [one of 27 coins is heavy or light].
So three weighings [27 cases] won't do it, but four [81 cases] can.
Google informs that someone claims there are three solutions.
At least one of them could not be completed within the prisoners' lifetimes; but it wasn't described.
I conclude from that there may be a solution that's faster than the one I posted.
So I re-thought my post. At least from the way I've presented it, it seems unique.
That opinion, however, might be related to the fact that I'm quite certain that I have two simply incomparable grandchildren.
... as all grandparents seem to think ...
The suggestion of subtracting N from the Nth term was a clue.
If you do it, you generate the third column in the following table.
Can you relate the numbers in the third column to N?
If you can, you've solved the puzzle.
N Nth term [Nth term]-N
= ======== ============
1 4 3
2 5 3
3 8 5
4 8 4
5 9 4
6 9 3
7 12 5
8 13 5
9 13 4
10 13 3
11 17 6
12 18 6
-- -- -
49 58 9
50 55 5
51 59 8
-- -- -
62 70 8
63 73 10
64 73 9
-- -- -
99 109 10
100 110 10
101 114 13[/code]
Edit to remove spoiler for a day or two...
Well, [1] yes that works and [2] it is too easy.
To be more responsive to Writersblock's question: What I have in mind is not mathematical.
The numbers have a property that surprisingly creates a new magic square.
That the new MS sums to 21 is just a piece of information that lets you verify that the MS you will have found is the one I had in mind.
Have Fun ... !
Without commenting on the nature of what you do,
do the same thing to each of the numbers to get a new srt of numbers.
The new set of numbers, each in its respective place, forms a 21 magic square.
Consider this 3x3 magic square, which sums horizontally, vertically and diagonally to 45:
5 22 18
28 15 2
12 8 25[/codebox]
Find a way to convert it to another 3x3 magic square that sums to 21.
Using only the symbols +, -, *, /, (, ) and each number only once,
you can generate the number 24 from 2, 2, 8, 8 as follows:
(2+2)*8 - 8 = 24.
Now do it for the numbers 3, 3, 8, 8.
Here's another:
I predict that Tony Dungy will weigh his options for another year with the Colts and finally decide to resign.
Will he re-up for another season, or will he quit?
Everyone knew that one Manning would be watching the other on TV next week, right?
How about those Giants?
Here's one for T.O. ... add a single tear coursing down the cheek.