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- Frequently Asked Questions (FAQS);faqs.451
-
-
-
- ==> games/connect.four.p <==
- Is there a winning strategy for Connect Four?
-
- ==> games/craps.p <==
- What are the odds in craps?
-
- ==> games/crosswords/cryptic/clues.p <==
- What are some clues (indicators) used in cryptics?
-
- ==> games/crosswords/cryptic/double.p <==
- Each clue has two solutions, one for each diagram; one of the answers
- to 1ac. determines which solutions are for which diagram.
-
- All solutions are in Chamber's and Webster's Third except for one solution
-
- ==> games/crosswords/cryptic/intro.p <==
- What are the rules for cluing cryptic crosswords?
-
- ==> games/go-moku.p <==
- For a game of k in a row on an n x n board, for what values of k and n is
- there a win? Is (the largest such) k eventually constant or does it increase
- with n?
-
- ==> games/hi-q.p <==
- What is the quickest solution of the game Hi-Q (also called Solitair)?
-
- For those of you who aren't sure what the game looks like:
-
-
- ==> games/jeopardy.p <==
- What are the highest, lowest, and most different scores contestants
- can achieve during a single game of Jeopardy?
-
- ==> games/knight.tour.p <==
- For what board sizes is a knight's tour possible?
-
- ==> games/nim.p <==
- Place 10 piles of 10 $1 bills in a row. A valid move is to reduce
- the last i>0 piles by the same amount j>0 for some i and j; a pile
- reduced to nothing is considered to have been removed. The loser
- is the player who picks up the last dollar, and they must forfeit
-
- ==> games/othello.p <==
- How good are computers at Othello?
-
- ==> games/risk.p <==
- What are the odds when tossing dice in Risk?
-
- ==> games/rubiks.clock.p <==
- How do you quickly solve Rubik's clock?
-
- ==> games/rubiks.cube.p <==
- What is known about bounds on solving Rubik's cube?
-
- ==> games/rubiks.magic.p <==
- How do you solve Rubik's Magic?
-
- ==> games/scrabble.p <==
- What are some exceptional scrabble games?
-
- ==> games/square-1.p <==
- Does anyone have any hints on how to solve the Square-1 puzzle?
-
- ==> games/think.and.jump.p <==
- THINK & JUMP: FIRST THINK, THEN JUMP UNTIL YOU
- ARE LEFT WITH ONE PEG! O - O O - O
- / \ / \ / \ / \
- O---O---O---O---O
-
- ==> games/tictactoe.p <==
- In random tic-tac-toe, what is the probability that the first mover wins?
-
- ==> geometry/K3,3.p <==
- Can three houses be connected to three utilities without the pipes crossing?
-
- _______ _______ _______
- | oil | |water| | gas |
-
- ==> geometry/bear.p <==
- If a hunter goes out his front door, goes 50 miles south, then goes 50
- miles west, shoots a bear, goes 50 miles north and ends up in front of
- his house. What color was the bear?
-
- ==> geometry/bisector.p <==
- If two angle bisectors of a triangle are equal, then the triangle is
- isosceles (more specifically, the sides opposite to the two angles
- being bisected are equal).
-
- ==> geometry/calendar.p <==
- Build a calendar from two sets of cubes. On the first set,
- spell the months with a letter on each face of three cubes.
- Use lowercase three-letter abbreviations for the names of all
- twelve months (e.g., "jan", "feb", "mar"). On the second set,
-
- ==> geometry/circles.and.triangles.p <==
- Find the radius of the inscribed and circumscribed circles for a triangle.
-
- ==> geometry/coloring/cheese.cube.p <==
- A cube of cheese is divided into 27 subcubes. A mouse starts at one
- corner and eats through every subcube. Can it finish in the middle?
-
- ==> geometry/coloring/dominoes.p <==
- There is a chess board (of course with 64 squares). You are given
- 21 dominoes of size 3-by-1 (the size of an individual square on
- a chess board is 1-by-1). Which square on the chess board can
- you cut out so that the 21 dominoes exactly cover the remaining
-
- ==> geometry/construction/4.triangles.6.lines.p <==
- Can you construct 4 equilateral triangles with 6 toothpicks?
-
- ==> geometry/construction/5.lines.with.4.points.p <==
- Arrange 10 points so that they form 5 rows of 4 each.
-
- ==> geometry/construction/square.with.compass.p <==
- Construct a square with only a compass and a straight edge.
-
- ==> geometry/cover.earth.p <==
- A thin membrane covers the surface of the earth. One square meter is
- added to the area of this membrane. How much is added to the radius and
- volume of this membrane?
-
- ==> geometry/dissections/circle.p <==
- Can a circle be cut into similar pieces without point symmetry
- about the midpoint? Can it be done with a finite number of pieces?
-
- ==> geometry/dissections/hexagon.p <==
- Divide the hexagon into:
- 1) 3 indentical rhombuses.
- 2) 6 indentical kites(?).
- 3) 4 indentical trapezoids.
-
- ==> geometry/dissections/square.70.p <==
- Since 1^2 + 2^2 + 3^2 + ... + 24^2 = 70^2, can a 70x70 sqaure be dissected into
- 24 squares of size 1x1, 2x2, 3x3, etc.?
-
- ==> geometry/dissections/square.five.p <==
- Can you dissect a square into 5 parts of equal area with just a straight edge?
-
- ==> geometry/duck.and.fox.p <==
- A duck is swimming about in a circular pond. A ravenous fox (who cannot
- swim) is roaming the edges of the pond, waiting for the duck to come close.
- The fox can run faster than the duck can swim. In order to escape,
- the duck must swim to the edge of the pond before flying away. Assume that
-
- ==> geometry/earth.band.p <==
- How much will a band around the equator rise above the surface if it
- is made one meter longer?
-
- ==> geometry/ham.sandwich.p <==
- Consider a ham sandwich, consisting of two pieces of bread and one of
- ham. Suppose the sandwich was dropped into a machine and spindled,
- torn and mutiliated. Is it still possible to divide the ham sandwich
- with a straight knife cut such that both the ham and the bread are
-
- ==> geometry/hike.p <==
- You are hiking in a half-planar woods, exactly 1 mile from the edge,
- when you suddenly trip and lose your sense of direction. What's the
- shortest path that's guaranteed to take you out of the woods? Assume
- that you can navigate perfectly relative to your current location and
-
- ==> geometry/hole.in.sphere.p <==
- Old Boniface he took his cheer,
- Then he bored a hole through a solid sphere,
- Clear through the center, straight and strong,
- And the hole was just six inches long.
-
- ==> geometry/ladders.p <==
- Two ladders form a rough X in an alley. The ladders are 11 and 13 meters
- long and they cross 4 meters off the ground. How wide is the alley?
-
- ==> geometry/lattice/area.p <==
- Prove that the area of a triangle formed by three lattice points is integer/2.
-
- ==> geometry/lattice/equilateral.p <==
- Can an equlateral triangle have vertices at integer lattice points?
-
- ==> geometry/rotation.p <==
- What is the smallest rotation that returns an object to its original state?
-
- ==> geometry/smuggler.p <==
- Somewhere on the high sees smuggler S is attempting, without much
- luck, to outspeed coast guard G, whose boat can go faster than S's. G
- is one mile east of S when a heavy fog descends. It's so heavy that
- nobody can see or hear anything further than a few feet. Immediately
-
- ==> geometry/table.in.corner.p <==
- Put a round table into a (perpendicular) corner so that the table top
- touches both walls and the feet are firmly on the ground. If there is
- a point on the perimeter of the table, in the quarter circle between
- the two points of contact, which is 10 cm from one wall and 5 cm from
-
- ==> geometry/tesseract.p <==
- If you suspend a cube by one corner and slice it in half with a
- horizontal plane through its centre of gravity, the section face is a
- hexagon. Now suspend a tesseract (a four dimensional hypercube) by one
- corner and slice it in half with a hyper-horizontal hyperplane through
-
- ==> geometry/tetrahedron.p <==
- Suppose you have a sphere of radius R and you have four planes that are
- all tangent to the sphere such that they form an arbitrary tetrahedron
- (it can be irregular). What is the ratio of the surface area of the
- tetrahedron to its volume?
-
- ==> geometry/tiling/rational.sides.p <==
- A rectangular region R is divided into rectangular areas. Show that if
- each of the rectangles in the region has at least one side with
- rational length then the same can be said of R.
-
- ==> geometry/tiling/rectangles.with.squares.p <==
- Given two sorts of squares, (axa) and (bxb), what rectangles can be tiled?
-
- ==> geometry/tiling/scaling.p <==
- A given rectangle can be entirely covered (i.e. concealed) by an
- appropriate arrangement of 25 disks of unit radius.
-
- Can the same rectangle be covered by 100 disks of 1/2 unit radius?
-
- ==> geometry/tiling/seven.cubes.p <==
- Consider 7 cubes of equal size arranged as follows. Place 5 cubes so
- that they form a Swiss cross or a + (plus). ( 4 cubes on the sides and
- 1 in the middle). Now place one cube on top of the middle cube and the
- seventh below the middle cube, to effectively form a 3-dimensional
-
- ==> group/group.01.p <==
- AEFHIKLMNTVWXYZ BCDGJOPQRSU
-
- ==> group/group.01a.p <==
- 147 0235689
-
- ==> group/group.02.p <==
- ABEHIKMNOPTXZ CDFGJLQRSUVWY
-
- ==> group/group.03.p <==
- BEJQXYZ DFGHLPRU KSTV CO AIW MN
-
- ==> group/group.04.p <==
- BDO P ACGJLMNQRSUVWZ EFTY HIKX
-
- ==> group/group.05.p <==
- CEFGHIJKLMNSTUVWXYZ ADOPQR B
-
- ==> group/group.06.p <==
- BCEGKMQSW DFHIJLNOPRTUVXYZ
-
- ==> induction/hanoi.p <==
- Is there an algorithom for solving the hanoi tower puzzle for any number
- of towers? Is there an equation for determining the minimum number of
- moves required to solve it, given a variable number of disks and towers?
-
- ==> induction/n-sphere.p <==
- With what odds do three random points on an n-sphere form an acute triangle?
-
- ==> induction/paradox.p <==
- What simple property holds for the first 10,000 integers, then fails?
-
- ==> induction/party.p <==
- You're at a party. Any two (different) people at the party have exactly one
- friend in common (the friend is also at the party). Prove that there is at
- least one person at the party who is a friend of everyone else. Assume that
- the friendship relation is symmetric and not reflexive.
-
- ==> induction/roll.p <==
- An ordinary die is thrown until the running total of the throws first
- exceeds 12. What is the most likely final total that will be obtained?
-
- ==> induction/takeover.p <==
- After graduating from college, you have taken an important managing position
- in the prestigious financial firm of "Mary and Lee".
- You are responsable for all the decisions concerning take-over bids.
- Your immediate concern is whether to take over "Financial Data".
-
- ==> logic/29.p <==
- Three people check into a hotel. They pay $30 to the manager and go
- to their room. The manager finds out that the room rate is $25 and
- gives $5 to the bellboy to return. On the way to the room the bellboy
- reasons that $5 would be difficult to share among three people so
-
- ==> logic/ages.p <==
- 1) Ten years from now Tim will be twice as old as Jane was when Mary was
- nine times as old as Tim.
-
- 2) Eight years ago, Mary was half as old as Jane will be when Jane is one year
-
- ==> logic/bookworm.p <==
- A bookworm eats from the first page of an encyclopedia to the last page.
- The bookworm eats in a straight line. The encyclopedia consists of ten
- 1000-page volumes. Not counting covers, title pages, etc., how many pages
- does the bookworm eat through?
-
- ==> logic/boxes.p <==
- Which Box Contains the Gold?
-
- Two boxes are labeled "A" and "B". A sign on box A says "The sign
- on box B is true and the gold is in box A". A sign on box B says
-
- ==> logic/calibans.will.p <==
- ----------------------------------------------
- | Caliban's Will by M.H. Newman |
- ----------------------------------------------
-
-
- ==> logic/camel.p <==
- An Arab sheikh tells his two sons that are to race their camels to a
- distant city to see who will inherit his fortune. The one whose camel
- is slower will win. The brothers, after wandering aimlessly for days,
- ask a wiseman for advise. After hearing the advice they jump on the
-
- ==> logic/centrifuge.p <==
- You are a biochemist, working with a 12-slot centrifuge. This is a gadget
- that has 12 equally spaced slots around a central axis, in which you can
- place chemical samples you want centrifuged. When the machine is turned on,
- the samples whirl around the central axis and do their thing.
-
- ==> logic/children.p <==
- A man walks into a bar, orders a drink, and starts chatting with the
- bartender. After a while, he learns that the bartender has three
- children. "How old are your children?" he asks. "Well," replies the
- bartender, "the product of their ages is 72." The man thinks for a
-
- ==> logic/condoms.p <==
- How can you have mutually safe sex with three women with only two condoms?
-
- ==> logic/dell.p <==
- How can I solve logic puzzles (e.g., as published by Dell) automatically?
-
- ==> logic/elimination.p <==
- 97 baseball teams participate in an annual state tournament.
- The way the champion is chosen for this tournament is by the same old
- elimination schedule. That is, the 97 teams are to be divided into
- pairs, and the two teams of each pair play against each other.
-
- ==> logic/family.p <==
- Suppose that it is equally likely for a pregnancy to deliver
- a baby boy as it is to deliver a baby girl. Suppose that for a
- large society of people, every family continues to have children
- until they have a boy, then they stop having children.
-
- ==> logic/flip.p <==
- How can a toss be called over the phone (without requiring trust)?
-
- ==> logic/friends.p <==
- Any group of 6 or more contains either 3 mutual friends or 3 mutual strangers.
- Prove it.
-
- ==> logic/hundred.p <==
- A sheet of paper has statements numbered from 1 to 100. Statement n says
- "exactly n of the statements on this sheet are false." Which statements are
- true and which are false? What if we replace "exactly" by "at least"?
-
- ==> logic/inverter.p <==
- Can a digital logic circuit with two inverters invert N independent inputs?
- The circuit may contain any number of AND or OR gates.
-
- ==> logic/josephine.p <==
- The recent expedition to the lost city of Atlantis discovered scrolls
- attributted to the great poet, scholar, philosopher Josephine. They
- number eight in all, and here is the first.
-
-
- ==> logic/locks.and.boxes.p <==
- You want to send a valuable object to a friend. You have a box which
- is more than large enough to contain the object. You have several
- locks with keys. The box has a locking ring which is more than large enough
- to have a lock attached. But your friend does not have the key to any
-
- ==> logic/mixing.p <==
- Start with a half cup of tea and a half cup of coffee. Take one tablespoon
- of the tea and mix it in with the coffee. Take one tablespoon of this mixture
- and mix it back in with the tea. Which of the two cups contains more of its
- original contents?
-
- ==> logic/number.p <==
- Mr. S. and Mr. P. are both perfect logicians, being able to correctly deduce
- any truth from any set of axioms. Two integers (not necessarily unique) are
- somehow chosen such that each is within some specified range. Mr. S.
- is given the sum of these two integers; Mr. P. is given the product of these
-
- ==> logic/riddle.p <==
- Who makes it, has no need of it. Who buys it, has no use for it. Who
- uses it can neither see nor feel it.
-
- Tell me what a dozen rubber trees with thirty boughs on each might be?
-
- ==> logic/river.crossing.p <==
- Three humans, one big monkey and two small monkeys are to cross a river:
- a) Only humans and the big monkey can row the boat.
- b) At all times, the number of human on either side of the
- river must be GREATER OR EQUAL to the number of monkeys
-
- ==> logic/ropes.p <==
- Two fifty foot ropes are suspended from a forty foot ceiling, about
- twenty feet apart. Armed with only a knife, how much of the rope can
- you steal?
-
- ==> logic/same.street.p <==
- Sally and Sue have a strong desire to date Sam. They all live on the
- same street yet neither Sally or Sue know where Sam lives. The houses
- on this street are numbered 1 to 99.
-
-
- ==> logic/self.ref.p <==
- Find a number ABCDEFGHIJ such that A is the count of how many 0's are in the
- number, B is the number of 1's, and so on.
-
- ==> logic/situation.puzzles.outtakes.p <==
- The following puzzles have been removed from my situation puzzles list,
- or never made it onto the list in the first place. There are a wide
- variety of reasons for the non-inclusion: some I think are obvious,
- some don't have enough of a story, some involve gimmicks that annoy me,
-
- ==> logic/situation.puzzles.p <==
- Jed's List of Situation Puzzles
-
- History:
- original compilation 11/28/87
-
- ==> logic/smullyan/black.hat.p <==
- Three logicians, A, B, and C, are wearing hats, which they know are either
- black or white but not all white. A can see the hats of B and C; B can see
- the hats of A and C; C is blind. Each is asked in turn if they know the color
- of their own hat. The answers are:
-
- ==> logic/smullyan/fork.three.men.p <==
- Three men stand at a fork in the road. One fork leads to Someplaceorother;
- the other fork leads to Nowheresville. One of these people always answers
- the truth to any yes/no question which is asked of him. The other always
- lies when asked any yes/no question. The third person randomly lies and
-
- ==> logic/smullyan/fork.two.men.p <==
- Two men stand at a fork in the road. One fork leads to Someplaceorother; the
- other fork leads to Nowheresville. One of these people always answers the
- truth to any yes/no question which is asked of him. The other always lies
- when asked any yes/no question. By asking one yes/no question, can you
-
- ==> logic/smullyan/integers.p <==
- Two logicians place cards on their foreheads so that what is written on the
- card is visible only to the other logician. Consecutive positive integers
- have been written on the cards. The following conversation ensues:
- A: "I don't know my number."
-
- ==> logic/smullyan/liars.et.al.p <==
- Of a group of n men, some always lie, some never lie, and the rest sometimes
- lie. They each know which is which. You must determine the identity of each
- man by asking the least number of yes-or-no questions.
-
- ==> logic/smullyan/painted.heads.p <==
- While three logicians were sleeping under a tree, a malicious child painted
- their heads red. Upon waking, each logician spies the child's handiwork as
- it applied to the heads of the other two. Naturally they start laughing.
- Suddenly one falls silent. Why?
-
- ==> logic/smullyan/priest.p <==
- A priest takes confession of all the inhabitants in a small town. He
- discovers that in N married pairs in the town, one of the pair has
- committed adultery. Assume that the spouse of each adulterer does not
- know about the infidelity of his or her spouse, but that, since it is
-
- ==> logic/smullyan/stamps.p <==
- The moderator takes a set of 8 stamps, 4 red and 4 green, known to the
- logicians, and loosely affixes two to the forehead of each logician so that
- each logician can see all the other stamps except those 2 in the moderator's
- pocket and the two on her own head. He asks them in turn
-
- ==> logic/timezone.p <==
- Two people are talking long distance on the phone; one is in an East-
- Coast state, the other is in a West-Coast state. The first asks the other
- "What time is it?", hears the answer, and says, "That's funny. It's the
- same time here!"
-
- ==> logic/unexpected.p <==
- Swedish civil defense authorities announced that a civil defense drill would
- be held one day the following week, but the actual day would be a surprise.
- However, we can prove by induction that the drill cannot be held. Clearly,
- they cannot wait until Friday, since everyone will know it will be held that
-
- ==> logic/verger.p <==
- A very bright and sunny Day
- The Priest didst to the Verger say:
- "Last Monday met I strangers three
- None of which were known to Thee.
-
- ==> logic/weighing/balance.p <==
- You are given N balls and a balance scale and told that
- one ball is slightly heavier or lighter than the other identical
- ones. The scale lets you put the same number of balls on each side
- and observe which side (if either) is heavier.
-
- ==> logic/weighing/box.p <==
- You have ten boxes; each contains nine balls. The balls in one box
- weigh 0.9 kg; the rest weigh 1.0 kg. You have one weighing on a
- scale to find the box containing the light balls. How do you do it?
-
- ==> logic/weighing/gummy.bears.p <==
- Real gummy drop bears have a mass of 10 grams, while imitation gummy
- drop bears have a mass of 9 grams. Spike has 7 cartons of gummy drop bears,
- 4 of which contain real gummy drop bears, the others imitation.
- Using a scale only once and the minimum number of gummy drop bears, how
-
- ==> logic/weighing/weighings.p <==
- Some of the supervisors of Scandalvania's n mints are producing bogus coins.
- It would be easy to determine which mints are producing bogus coins but,
- alas, the only scale in the known world is located in Nastyville,
- which isn't on very friendly terms with Scandalville. In fact, Nastyville's
-
- ==> logic/zoo.p <==
- I took some nephews and nieces to the Zoo, and we halted at a cage marked
-
- Tovus Slithius, male and female.
- Beregovus Mimsius, male and female.
-
- ==> physics/balloon.p <==
- A helium-filled balloon is tied to the floor of a car that makes a
- sharp right turn. Does the balloon tilt while the turn is made?
- If so, which way? The windows are closed so there is no connection
- with the outside air.
-
- ==> physics/bicycle.p <==
- A boy, a girl and a dog go for a 10 mile walk. The boy and girl can
- walk 2 mph and the dog can trot at 4 mph. They also have bicycle
- which only one of them can use at a time. When riding, the boy and
- girl can travel at 12 mph while the dog can peddle at 16 mph.
-
- ==> physics/boy.girl.dog.p <==
- A boy, a girl and a dog are standing together on a long, straight road.
- Simulataneously, they all start walking in the same direction:
- The boy at 4 mph, the girl at 3 mph, and the dog trots back and forth
- between them at 10 mph. Assume all reversals of direction instantaneous.
-
- ==> physics/brick.p <==
- What is the maximum overhang you can create with an infinite supply of bricks?
-
- ==> physics/cannonball.p <==
- A person in a boat drops a cannonball overboard; does the water level change?
-
- ==> physics/dog.p <==
- A body of soldiers form a 50m-by-50m square ABCD on the parade ground.
- In a unit of time, they march forward 50m in formation to take up the
- position DCEF. The army's mascot, a small dog, is standing next to its
- handler at location A. When the
-
- ==> physics/magnets.p <==
- You have two bars of iron. One is magnetic, the other is not. Without
- using any other instrument (thread, filings, other magnets, etc.), find
- out which is which.
-
- ==> physics/milk.and.coffee.p <==
- You are just served a hot cup of coffee and want it to be as hot as possible
- when you drink it some number of minutes later. Do you add milk when you get
- the cup or just before you drink it?
-
- ==> physics/mirror.p <==
- Why does a mirror appear to invert the left-right directions, but not up-down?
-
- ==> physics/monkey.p <==
- Hanging over a pulley, there is a rope, with a weight at one end.
- At the other end hangs a monkey of equal weight. The rope weighs
- 4 ounces per foot. The combined ages of the monkey and it's mother
- is 4 years. The weight of the monkey is as many pounds as the mother
-
- ==> physics/particle.p <==
- What is the longest time that a particle can take in travelling between two
- points if it never increases its acceleration along the way and reaches the
- second point with speed V?
-
- ==> physics/pole.in.barn.p <==
- Accelerate a pole of length l to a constant speed of 90% of the speed of
- light (.9c). Move this pole towards an open barn of length .9l (90%
- the length of the pole). Then, as soon as the pole is fully inside the
- barn, close the door. What do you see and what actually happens?
-
- ==> physics/resistors.p <==
- What are the resistances between lattices of resistors in the shape of a:
-
- 1. Cube
-
-
- ==> physics/sail.p <==
- A sailor is in a sailboat on a river. The water (current) is flowing
- downriver at a velocity of 3 knots with respect to the land. The wind
- (air velocity) is zero, with respect to the land. The sailor wants
- to proceed downriver as quickly as possible, maximizing his downstream
-
- ==> physics/skid.p <==
- What is the fastest way to make a 90 degree turn on a slippery road?
-
- ==> physics/spheres.p <==
- Two spheres are the same size and weight, but one is hollow. They are
- made of uniform material, though of course not the same material. Without
- a minimum of apparatus, how can I tell which is hollow?
-
- ==> physics/wind.p <==
- Is a round-trip by airplane longer or shorter if there is wind blowing?
-
- ==> probability/amoeba.p <==
- A jar begins with one amoeba. Every minute, every amoeba
- turns into 0, 1, 2, or 3 amoebae with probability 25%
- for each case ( dies, does nothing, splits into 2, or splits
- into 3). What is the probability that the amoeba population
-
- ==> probability/apriori.p <==
- An urn contains one hundred white and black balls. You sample one hundred
- balls with replacement and they are all white. What is the probability
- that all the balls are white?
-
- ==> probability/cab.p <==
- A cab was involved in a hit and run accident at night. Two cab companies,
- the Green and the Blue, operate in the city. Here is some data:
-
- a) Although the two companies are equal in size, 85% of cab
-
- ==> probability/coincidence.p <==
- Name some amazing coincidences.
-
- ==> probability/coupon.p <==
- There is a free gift in my breakfast cereal. The manufacturers say
- that the gift comes in four different colours, and encourage one to
- collect all four (& so eat lots of their cereal). Assuming there is
- an equal chance of getting any one of the colours, what is the
-
- ==> probability/darts.p <==
- Peter throws two darts at a dartboard, aiming for the center. The
- second dart lands farther from the center than the first. If Peter now
- throws another dart at the board, aiming for the center, what is the
- probability that this third throw is also worse (i.e., farther from
-
- ==> probability/flips.p <==
- Consider a run of coin tosses: HHTHTTHTTTHTTTTHHHTHHHHHTHTTHT
-
- Define a success as a run of one H or T (as in THT or HTH). Use two
- different methods of sampling. The first method would consist of
-
- ==> probability/flush.p <==
- Which set contains more flushes than the set of all possible hands?
- (1) Hands whose first card is an ace
- (2) Hands whose first card is the ace of spades
- (3) Hands with at least one ace
-
- ==> probability/hospital.p <==
- A town has two hospitals, one big and one small. Every day the big
- hospital delivers 1000 babies and the small hospital delivers 100
- babies. There's a 50/50 chance of male or female on each birth.
- Which hospital has a better chance of having the same number of boys
-
- ==> probability/icos.p <==
- The "house" rolls two 20-sided dice and the "player" rolls one
- 20-sided die. If the player rolls a number on his die between the
- two numbers the house rolled, then the player wins. Otherwise, the
- house wins (including ties). What are the probabilities of the player
-
- ==> probability/intervals.p <==
- Given two random points x and y on the interval 0..1, what is the average
- size of the smallest of the three resulting intervals?
-
- ==> probability/lights.p <==
- Waldo and Basil are exactly m blocks west and n blocks north from Central Park,
- and always go with the green light until they run out of options. Assuming
- that the probability of the light being green is 1/2 in each direction and
- that if the light is green in one direction it is red in the other, find the
-
- ==> probability/lottery.p <==
- There n tickets in the lottery, k winners and m allowing you to pick another
- ticket. The problem is to determine the probability of winning the lottery
- when you start by picking 1 (one) ticket.
-
-
- ==> probability/particle.in.box.p <==
- A particle is bouncing randomly in a two-dimensional box. How far does it
- travel between bounces, on avergae?
-
- Suppose the particle is initially at some random position in the box and is
-
- ==> probability/pi.p <==
- Are the digits of pi random (i.e., can you make money betting on them)?
-
- ==> probability/random.walk.p <==
- Waldo has lost his car keys! He's not using a very efficient search;
- in fact, he's doing a random walk. He starts at 0, and moves 1 unit
- to the left or right, with equal probability. On the next step, he
- moves 2 units to the left or right, again with equal probability. For
-
- ==> probability/reactor.p <==
- There is a reactor in which a reaction is to take place. This reaction
- stops if an electron is present in the reactor. The reaction is started
- with 18 positrons; the idea being that one of these positrons would
- combine with any incoming electron (thus destroying both). Every second,
-