Amusements in Mathematics eBook

Henry Dudeney
This eBook from the Gutenberg Project consists of approximately 597 pages of information about Amusements in Mathematics.

Amusements in Mathematics eBook

Henry Dudeney
This eBook from the Gutenberg Project consists of approximately 597 pages of information about Amusements in Mathematics.
| 4n+1 | n " n+1 |2n squared+5n-2 | 2n |2n squared+3n-4 |2(2n squared+4n-3)| | 4n-1 | n-1 " n |2(n-1) squared+5n-7 | 2n |2n squared+3n-4 |4n squared+4n-9 | +----------+-------------+-------------+----------+---------
---+-----------+
SECOND METHOD.
+---------+--------------------------+----------------------
---+-----------+ |Total No.| L MOVEMENT. | U MOVEMENT. | | | of +-------------+------------+----------+--------------+ Total No. | |Counters.| No. of | No. of | No. of | No. of | of Moves. | | | Counters. | Moves. | Counters.| Moves. | | +---------+-------------+------------+----------+-----------
---+-----------+ | 4n | n and n |2n squared+3n-4 | 2n | 2(n-1) squared+5n-2 |4(n squared+n-1) | | 4n-2 | n-1 " n-1 |2(n-1) squared+3n-7| 2n | 2(n-1) squared+5n-2 |4n squared-5 | | 4n+1 | n " n |2n squared+3n-4 | 2n+1 | 2n squared+5n-2 |2(2n squared+4n-3)| | 4n-1 | n " n |2n squared+3n-4 | 2n-1 | 2(n-1) squared+5n-7 |4n squared+4n-9 | +---------+-------------+------------+----------+-----------
---+-----------+

More generally we may say that with m counters, where m is even and greater than 4, we require (m squared + 4m — 16)/4 moves; and where m is odd and greater than 3, (m squared + 6m — 31)/4 moves.  I have thus shown the reader how to find the minimum number of moves for any case, and the character and direction of the moves.  I will leave him to discover for himself how the actual order of moves is to be determined.  This is a hard nut, and requires careful adjustment of the L and the U movements, so that they may be mutually accommodating.

216.—­THE EDUCATED FROGS.

The following leaps solve the puzzle in ten moves:  2 to 1, 5 to 2, 3 to 5, 6 to 3, 7 to 6, 4 to 7, 1 to 4, 3 to 1, 6 to 3, 7 to 6.

217.—­THE TWICKENHAM PUZZLE.

Play the counters in the following order:  K C E K W T C E H M K W T A N C E H M I K C E H M T, and there you are, at Twickenham.  The position itself will always determine whether you are to make a leap or a simple move.

218.—­THE VICTORIA CROSS PUZZLE.

In solving this puzzle there were two things to be achieved:  first, so to manipulate the counters that the word VICTORIA should read round the cross in the same direction, only with the V on one of the dark arms; and secondly, to perform the feat in the fewest possible moves.  Now, as a matter of fact, it would be impossible to perform the first part in any way whatever if all the letters of the word were different; but as there are two I’s, it can be done by making these letters change places—­that is, the first I changes from the 2nd place to the 7th, and the second I from the 7th place to the 2nd.  But the point I referred to, when introducing the puzzle, as a little remarkable is this:  that a solution in twenty-two moves is obtainable by moving the letters in the order of the following words:  “A VICTOR!  A VICTOR!  A VICTOR I!”

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Amusements in Mathematics from Project Gutenberg. Public domain.