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Posts posted by superprismatic
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Circular hopscotch is played on six
squares arranged in a circle. A coin
is tossed and a player starting on
square 1 jumps, advancing either 1 or
2 squares according as the coin falls
head or tail. When he lands on square
6, he is 'out'. Each player gets a
score equal to the number of squares
stood on or passed over during his
turn. (Thus the only possible scores
are multiples of 6.) What is the
average number of points a player may
expect to score?
SUPERPRISMATIC CLARIFICATION:
Each advancement ( 1 or 2 squares)
is preceded by a separate coin toss.
That is to say, a single coin toss
does not control all the jumps a
player makes.
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[5, 12, 23, 10, 28, 4, 11, 11, 12, 4, 28, 19, 21, 12, 12, 27, 29, 11,
11, 21, 12, 18, 29, 24, 23, 23, 12, 28, 10, 28, 29, 0, 2, 21, 2, 23,
14, 28, 10, 18, 21, 4, 2, 28, 2, 4, 6, 23, 29, 27, 14, 29, 6, 19, 10, 28, 5, 28, 23, 29, 24]
basically i wrote an algorithm that tries random positions until it finds one that works.
(the 0 would be the king)
I did a depth-first tree search. When I reorder the couples to place, I find that I can get very many solutions. I had hoped that someone would come up with a more enlightened approach than the ones you and I found.
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Check that real quick...the following:
Should have read:
We know that BOTH X AND Y are integral. So we know that x-y2 = y.
Please explain further. If x and y are both integral, all I can see is that x-y2 is integral.
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If he is hosting several different parties do they need to be seated apart according to their anniversary at all parties or just at the party for their anniversary party?
This is just for one of his many parties. All attendees are celebrating their anniversaries on the date of the dinner. The poor chief of protocol has to make the seating chart for all the other dinners as well! If you can find a good algorithm for him to use, you will simplify his life enormously!
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You seat them in the order that they arrive.
I didn't mean in time order. How do you order them around the table?
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Clarify:
.
- Since the table is round, between any two persons there are two sets of intervening people.
Do we always take the smaller number?
Doh! Forget that one ... but,
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- The King sits after all the spacings have been set.
So the King does not apply to the separation count?
To be specific, if a couple are on either side of the king, they are celebrating their 2nd anniversary.
So, the king counts in the separation. I hope this clears it up.
- Since the table is round, between any two persons there are two sets of intervening people.
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A benevolent king hosts wedding
anniversary dinners for some of
his subjects on several days
each year. He has a 61-seat
round table at which to seat
30 couples who are celebrating
their wedding anniversaries on
the day of the dinner. He has
decreed that each couple will
be seated N-seats away from each
other if they are celebrating
their Nth anniversary.
So, for example, if a couple
has been married 1 year, they
will be seated next to each
other; married 2 years and they
will have one person between them;
etc. The king will sit at the
one remaining seat. Imagine that
you are the king's chief of
protocol and you are given the
task of arranging the seating
for the 30 couples with the
following anniversary distribution:
# couples years married
2 2
2 4
1 5
1 6
2 10
2 11
3 12
1 14
1 18
1 19
2 21
3 23
1 24
1 27
4 28
3 29
[/code]Being a Mathematics buff, you
realize that this can be done
because 61 is a prime. So, in what
order do you seat the 60 guests?
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Oh that's true, I had forgotten about the quadratic formula, thx.
But using the formula will create 2 different set of answers
for:
* f=(xy + sqrt(x2y2 + 4xy))/(2y)
* f=(xy - sqrt(x2y2 + 4xy))/(2y)
So it's starting to get more complex, but I'll give it a try
You can forget the second one. After all, it is negative and it is clear that the solution must be positive.
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Password is: BUGLE
Integer is 992
Don't know the other integer.
Answer to the second is *MUCH* harder!
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Members of a certain gang communicate
with each other by means of the
following system. The square root of
an agreed-upon integer is extracted
and carried out to a number of decimal
places equal to the length of the
message. Then each letter of the
message is advanced (cyclically) in
the normal alphabetic sequence a
number of places given by the
corresponding digit of the decimal
part. For example, if the number
agreed upon were 2, the word STOP
would be enciphered as WUSR since
Sqrt(2)=1.4142 to four decimal places.
One day a detective found the
following message on the body of a
gangster slain by a member of a rival
mob: TJYSZPVM OS FBIPI. He assumed
(correctly) that this began PASSWORD
IS. What is the password?
SUPERPRISMATIC ANECDOTE ABOUT THIS:
I know of two solutions to this --
the one Penney intended as well as
one that two smart co-workers of his
found. They found a 31-digit integer
which also gave a (different) common
English word as the password. For
this to happen, of course, the
fractional part of its square root
must begin with the same ten decimal
digits that Penney's gave, then
somehow differ in the next five.
A super-hard secondary problem would
be to find this 31-digit number. By
the way, I don't know what that
31-digit number is -- I only know
what password it produces.
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By the way, I found my solution wrong... sorry 4 that
I rechecked the algebra and I got stuck "somewhere"
Having that
f(x, y) = x + 1/(y + 1/f(x, y)) ......... 1
I reduce as follows, .... I replaced f(x, y) with only f
f = x + 1/(y + 1/f) .................. 1
f = x + 1/((yf + 1)/f)
f = ((xyf + x)/f + 1)/((yf + 1)/f)
f = ((xyf + x + f)/f)/((yf + 1)/f)
f = (xyf + x + f)/(yf + 1)
yf2 + f = xyf + x + f
yf2 = xyf + x
yf2 - xyf - x = 0 .......... 2
I believe equation 2 (the last reduction) can be factorized to have an expression f = g(x, y) where g(x, y) doesn't have f as part of it. Unfortunately, I haven't been able to factorize the expression, so I'm not even sure if that's possible.
If possible, the f = g(x, y) could then be sustituted in the f(p, q) - 3f(r, s) = 1/2 expression, getting an equation involving the p, q, r, s parameters and then any combination of values for p, q, r, s that satisfies the equation is a solution.
If anyone is able to factorize equation 2 please let me know.
*Note: Is easier to follow the reductions I did if writing them into paper to see the algebraic form. All the parenthesis in here make it harder to follow.
Use the quadratic formula to get f=(xy + sqrt(x2y2 + 4xy))/(2y).
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When x = yc0 (c0 times any y) then the polynomial will have c0 and 1 + c1y + c2c01y2 + .. + cnc0n-1yn as factors.
Suppose c0 = 1. Then what?
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N = 521
A full period of the Fibonacci sequence modulo 521 is:
0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 89, 466, 34, 500, 13, 513, 5, 518, 2, 520, 1
When placed in ascending order, you get
0, 1, 1, 1, 2, 2, 3, 5, 5, 8, 13, 13, 21, 34, 34, 55, 89, 89, 144, 233, 377, 466, 500, 513, 518, 520
Assigning to each letter,
A 0
B 1
C 1
D 1
E 2
F 2
G 3
H 5
I 5
J 8
K 13
L 13
M 21
N 34
O 34
P 55
Q 89
R 89
S 144
T 233
U 377
V 466
W 500
X 513
Y 518
Z 520
This is the correct key for encoding and decoding the text presented in the question.
mmiguel1's got it!
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I'm not sure that I understand the instruction in this puzzle. Is the following interpretation of the problem correct?
1) A number N is chosen, where N is larger than the largest number in the cipher code.
2) The fibonnaci series F(i) modulo N has a period of 26, meaning that for any index i, F(i) mod N == F(i + 26) mod N
3) The list of 26 values from within 1 period is sorted in ascending order, and each number assigned a letter according to its ordinal index (smallest number is A, second smallest is B, and so on).
4) This transformation is then applied to "Gardening is just a soil sport" to get ( 3 0 89 1 2 34 5 34 3/ 5 144 / 8 377 144 233 / 0 / 144 34 5 13 /144 55 34 89 233 )
5) Find N
PS. Also, does this sequence start at 1 or 0? Many references for the fibonnacci series start at 0.
Your interpretation in 1 through 5 is correct. The sequence starts with 1, although that may not matter if 0, 1, 1 occurs in the 26-long cycle (because of your clarification #3). Also, if any number occurs more than once in the cycle, more than one letter is assigned to it.
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The value of the sequence 1, 2, 3, 5,
8, ... , where each member is the sum
of the two preceding, are reduced
mod N; i.e., if any value is greater
than N, N is subtracted. The
resulting sequence has period 26, and
the values, in numerical order, are
assigned to the letters A to Z. Note
that by this scheme the same number
may represent more than one letter.
The message, "Gardening is just a soil
sport," converted into numbers by this
process becomes: 3 0 89 1 2 34 5 34 3
/ 5 144 / 8 377 144 233 / 0 / 144 34
5 13 / 144 55 34 89 233. Find N.
SUPERPRISMATIC CORRECTION: "greater
than" should be "greater than or equal
to" in the explanation of "mod N" in
the first sentence. Walter Penney
was fallible.
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non-zero perfect squares?
Yes.
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In the game of Subtract-a-Square two
players take alternately from a pile
of counters, the only restriction
being that the number taken must be
a perfect square. The player wins
who succeeds in getting the last
counter. How many should a player
take if there are now 50 counters
in the pile?
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I need my day's allowance of Walter Penney puzzle!
Lemma: if the boy can reduce the groups on the daisy to an even number of 1's, an even number of 2's, an even number of 3's, or any combination of even groups of 1 to 3, he can win. Likewise, if the girl can reduce the groups to combination of even groups of 1 to 3, she can win.
Start from the group of 8, let the boy pick the fourth petal, leaving the daisy with groups of 2, 3, and 4. You can easily see that doesn't matter what the girl pick next, the boy can reduce it to his winning combination within 1 move or 2 moves.
You found a second solution. Penney gave another.
Take 1 from the end of the 8, leaving 7 and 2. It works as well.
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Two lovers decide to test their love
with a daisy. The particular daisy has
13 petals, and they agree to pluck
alternately, taking either one petal or
two adjacent petals. The boy picks
one, saying, "She loves me." The girl
picks two adjacent petals, leaving
groups of 8 and 2, saying, "He loves me
not." How should the boy continue if
he wants to end up in love in spite of
any move his opponent (?) makes?
SUPERPRISMATIC CLARIFICATION: The boy
must pick the last of the petals to get
what he wishes. Also, "adjacent petals"
refers to adjacency on the original
13-petal configuration in which each
petal only has 2 adjacent petals -- one
on either side.
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Bushindo has it!
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The numbers from 1 to 12 are written on
the faces of a cube, two numbers to a
face, in such a way that the sum of the
numbers on any face is the same as the
sum of the numbers on the opposite face.
One of the numbers on the top face is
selected, the cube rolled 90 degrees so
that one of the adjacent faces comes on
top, a number selected from this face,
etc. The sequence 2, 1, 5, 3, 4, 7, 2,
10, 6, 11, 8, 9, 12, 3, 11, 9, 10, 7,
11, 12, 4, 1, 6, 5, 7 is generated in
this manner. How are the numbers
arranged on the face of the cube?
The word "face" in the last sentence should be "faces"
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The numbers from 1 to 12 are written on
the faces of a cube, two numbers to a
face, in such a way that the sum of the
numbers on any face is the same as the
sum of the numbers on the opposite face.
One of the numbers on the top face is
selected, the cube rolled 90 degrees so
that one of the adjacent faces comes on
top, a number selected from this face,
etc. The sequence 2, 1, 5, 3, 4, 7, 2,
10, 6, 11, 8, 9, 12, 3, 11, 9, 10, 7,
11, 12, 4, 1, 6, 5, 7 is generated in
this manner. How are the numbers
arranged on the face of the cube?
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SUGGESTIVE PROPAGANDA
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The polynomial X23+X+1 can be
expressed as the product of 2 factors.
If the powers of X, excluding the
constant term, in one of these factors
is converted into letters (1=A, 2=B,
etc.), it is observed that these letters
can be anagrammed into a three-word
phrase meaning, with a certain stretch
of the imagination, "a peculiarity of a
seat in a church gallery." What is the
phrase?
SUPERPRISMATIC CLARIFICATION: Perhaps
the word "powers" should be replaced
by "exponents" to better nail down the
intent of the puzzle.
SUPERPRISMATIC OBSERVATION: Walter
Penney did not have access to computer
algebra software!
in New Logic/Math Puzzles
Posted
A message is written in the cells of
a rectangle having six rows and eight
columns. A piece of cardboard with
twelve holes cut out is placed over
this and the twelve letters exposed
read off. The cardboard is given a
180 degree turn and the next twelve
letters read off. At this point the
cardboard is turned over around the
vertical axis and twelve more letters
are read off. A final turn of 180
degrees allows the last 12 letters to
be read off. The result is: UNOLU
WUPNU ELGDH RDGHW EDEOL HTELH
TYEYP NAAWA SIOAO WAE. Read the
message.
SUPERPRISMATIC CLARIFICATIONS:
(1) The message is written in by rows,
left-to-right and top row to bottom
row.
(2) The sets of twelve are read off
left-to-right and top-to-bottom.
(3) The cryptogram is written in
groups of five for easy reading.
The spaces are irrelevant.
(4) Remember that the cutouts must
be designed so that any letter is
exposed in one, and only one, of the
four orientations of the piece of
cardboard
(5) It might be instructive to
design such a scheme yourself out of
graph paper to see how to make good
cutouts and to see how letters are
scrambled by it.