ASF Puzzles & Conundrums Thread

[bellenuit]

Another easy chessboard problem......

You have an infinitely large chessboard (one that has an infinite number of rows and columns) where each square has sides of 2cm. You throw a perfectly round 1cm diameter coin onto the chessboard. Assuming it always lands flat, what is the probability that it will land straddling two or more squares.

Answers in Spoilers

 

[bellenuit]

A few easy ones.

No. 1

Anne and Jessica were working on the computer along with their friends Sandy and Nicole. Suddenly, I heard a crash and then lots of shouts. I rushed in to find out what was going on, finding the computer monitor on the ground, surrounded with broken glass!

Jessica saying, "It wasn't me!"
Sandy saying, "It was Nicole!"
Anne yelled, "No, it was Sandy!"
With a straight face Nicole said, "Sandy's a liar."

Only one of them was telling the truth, so who knocked over the monitor?

No. 2

How can you cut a traditional circular cake into 8 equal size pieces, with only 3 cuts?

 

[cynic]

A few easy ones.

No. 1

Anne and Jessica were working on the computer along with their friends Sandy and Nicole. Suddenly, I heard a crash and then lots of shouts. I rushed in to find out what was going on, finding the computer monitor on the ground, surrounded with broken glass!

Jessica saying, "It wasn't me!"
Sandy saying, "It was Nicole!"
Anne yelled, "No, it was Sandy!"
With a straight face Nicole said, "Sandy's a liar."

Only one of them was telling the truth, so who knocked over the monitor?

No. 2

How can you cut a traditional circular cake into 8 equal size pieces, with only 3 cuts?

It occurs to me that No. 1. can serve as the basis for a further puzzle, if, instead of having only one girl telling the truth, posing the question of whodunnit when only one of the girls is lying.

 

[bellenuit]

This one requires a fair bit of thinking....

Draw a side view of this wooden object

This is the top and front view of a real three dimensional wooden object. Real implies it has thickness and is not, for instance, two flat plates of zero thickness at right angles. Any hidden sides are shown with dotted lines (and there are none shown on these two views implying all sides are visible). The inner square represents a square hole running through the object (it is not just a square drawn on the object). Its lines are solid because the edges of the square are visible and not hidden.



You are to draw a view of the object looking at it from the left hand side (with any hidden sides shown with dotted lines).

To help clarify, the following answer would be false.



Apart from the fact it is not a proper left side view, it is false because if it were that shape, the original two drawings would be represented as follows to show the hidden edges and they are obviously not.




Answers in Spoilers

 

[noco]

Not sure if it is the right thread but it makes for interesting reading.


1. The Post Office
Get ready to imagine a world without the post office. They are so deeply in
financial trouble that there is probably no way to sustain it long term. Email,
Fed Ex, and UPS have just about wiped out the minimum revenue needed to keep the
post office alive. Most of your mail every day is junk mail and bills.

2. The Cheque
Britain is already laying the groundwork to do away with cheque by 2018. It costs
the financial system billions of dollars a year to process cheques. Plastic
cards and online transactions will lead to the eventual demise of the
cheque. This plays right into the death of the post office. If you
never paid your bills by mail and never received them by mail, the post office
would absolutely go out of business.

3. The Newspaper
The younger generation simply doesn't read the newspaper. They certainly don't
subscribe to a daily delivered print edition. That may go the way of the
milkman and the laundry man. As for reading the paper online, get ready to
pay for it. The rise in mobile Internet devices and e-readers has caused
all the newspaper and magazine publishers to form an alliance. They have
met with Apple, Amazon, and the major cell phone companies to develop a model
for paid subscription services.

4. The Book
You say you will never give up the physical book that you hold in your hand and turn
the literal pages I said the same thing about downloading music from
iTunes. I wanted my hard copy CD. But I quickly changed my mind when
I discovered that I could get albums for half the price without ever leaving
home to get the latest music. The same thing will happen with books.
You can browse a bookstore online and even read a preview chapter before you
buy. And the price is less than half that of a real book. And think
of the convenience! Once you start flicking your fingers on the screen
instead of the book, you find that you are lost in the story, can't wait to see
what happens next, and you forget that you're holding a gadget instead of a
book.

5. The Land Line Telephone
Unless you have a large family and make a lot of local calls, you don't need it
anymore. Most people keep it simply because they've always had it.
But you are paying double charges for that extra service. All the cell
phone companies will let you call customers using the same cell provider for no
charge against your minutes.

6. Music
This is one of the saddest parts of the change story. The music industry is
dying a slow death. Not just because of illegal downloading. It's
the lack of innovative new music being given a chance to get to the people who
would like to hear it. Greed and corruption is the problem. The
record labels and the radio conglomerates are simply self-destructing.
Over 40% of the music purchased today is "catalogue items," meaning traditional
music that the public is familiar with. Older established artists.
This is also true on the live concert circuit. To explore this fascinating
and disturbing topic further, check out the book, "Appetite for
Self-Destruction" by Steve Knopper, and the video documentary, "Before the Music Dies."

7. Television Revenues
To the networks are down dramatically. Not just because of the economy.
People are watching TV and movies streamed from their computers. And
they're playing games and doing lots of other things that take up the time that
used to be spent watching TV. Prime time shows have degenerated down to
lower than the lowest common denominator. Cable rates are skyrocketing and
commercials run about every 4 minutes and 30 seconds. I say good riddance
to most of it. It's time for the cable companies to be put out of our
misery. Let the people choose what they want to watch online and through Netflix.

8. The "Things" That You Own
Many of the very possessions that we used to own are still in our lives, but we may
not actually own them in the future. They may simply reside in "the
cloud." Today your computer has a hard drive and you store your pictures,
music, movies, and documents. Your software is on a CD or DVD, and you can
always re-install it if need be. But all of that is changing. Apple,
Microsoft, and Google are all finishing up their latest "cloud services."
That means that when you turn on a computer, the Internet will be built into the
operating system. So, Windows, Google, and the Mac OS will be tied
straight into the Internet. If you click an icon, it will open something
in the Internet cloud. If you save something, it will be saved to the
cloud. And you may pay a monthly subscription fee to the cloud
provider. In this virtual world, you can access your music or your books,
or your whatever from any laptop or handheld device. That's the good
news. But, will you actually own any of this "stuff" or will it all be
able to disappear at any moment in a big "Poof?" Will most of the things
in our lives be disposable and whimsical? It makes you want to run to the
closet and pull out that photo album, grab a book from the shelf, or open up a
CD case and pull out the insert.

9. Joined Handwriting (Cursive Writing)
Already gone in some schools who no longer teach "joined handwriting" because nearly
everything is done now on computers or keyboards of some type (pun not intended)

10. Privacy
If there ever was a concept that we can look back on nostalgically, it would be
privacy. That's gone. It's been gone for a long time anyway..
There are cameras on the street, in most of the buildings, and even built into
your computer and cell phone. But you can be sure that 24/7, "They" know
who you are and where you are, right down to the GPS coordinates, and the Google
Street View. If you buy something, your habit is put into a zillion
profiles, and your ads will change to reflect those habits.. "They" will
try to get you to buy something else. Again and again and again.

All we will have left that which can't be changed.......are our "Memories".

Logic is dead.
Excellence is punished.
Mediocrity is rewarded.
and
Dependency is to be revered.

When people rob banks they go to prison.
When they rob the taxpayer they get re-elected

 

[bellenuit]

One to get you going for 2016.

The countdown to the new year:
10 9 8 7 6 5 4 3 2 1 = 2016

Your task is to fill in the gaps between those 10 sequential numbers on the left of the = sign so that the equation = 2016. You can use +, -, * and /. You can also use parenthesis to ensure there is no ambiguity in the order the calculations are performed, although if omitted the standard order of calculation; *, / before +, -; will be assumed.

The countdown order must be maintained and you cannot concatenate adjacent numbers (for example, you cannot treat the three numbers 7 6 5 as the single number 765)

So, for example, a solution could look like this....

10 * (9+8) -7............. =2016

The answer isn't unique as there are several ways to make the equation work.


Answers in spoilers thread please.

 

[bellenuit]

Apparently >80% of people get this wrong.

Jack is looking at Anna and Anna is looking at George. Jack is married and George is not.

Question:

On the information given above, is a married person looking at an unmarried person?

A. Yes
B. No
C. Cannot be determined

Answers in Spoilers please.

 

[bellenuit]

A very hard one to keep you busy over the Australia Day period. It requires poetry and math.

Can you express this equation in words in the format of a Limerick?



Answers (and there can be more than one obviously) in Spoilers please.

 

[SirRumpole]

I'm sure the people here will solve this in an instant !

'No winning answers yet' to British spy agency's Christmas puzzle challenge

http://www.abc.net.au/news/2016-01-...o-british-spy-agency-christmas-puzzle/7127758

 

[bellenuit]

A shadowy puzzle

You have a light source that throws light out in all directions. You are to construct a closed room around that light source using straight perpendicular walls which meet each other at corners. The shape you end up with must be such that every wall is either partly or fully shaded from the light source (e.g. every wall of the room is either partly or fully shaded from the light source by other walls in the room).

There is no limit to the number of walls you require to do this, but those that can do it with the least number of walls are the best solutions.

There is no trick to the question. We are just looking for a two dimensional shape (as if looking down from above). You assume the position of the light source is fixed and design your shape from that, so you are NOT required to produce a shape that subsequently must have all walls partly/fully shaded if the light source is move to another position. Also, it is a continuous shape, where the walls join each other at their ends only with the first wall meeting up with the last to form a complete closed shape with the light source within it.

 

[bellenuit]

A shadowy puzzle

You have a light source that throws light out in all directions. You are to construct a closed room around that light source using straight perpendicular walls which meet each other at corners. The shape you end up with must be such that every wall is either partly or fully shaded from the light source (e.g. every wall of the room is either partly or fully shaded from the light source by other walls in the room).

There is no limit to the number of walls you require to do this, but those that can do it with the least number of walls are the best solutions.

There is no trick to the question. We are just looking for a two dimensional shape (as if looking down from above). You assume the position of the light source is fixed and design your shape from that, so you are NOT required to produce a shape that subsequently must have all walls partly/fully shaded if the light source is move to another position. Also, it is a continuous shape, where the walls join each other at their ends only with the first wall meeting up with the last to form a complete closed shape with the light source within it.

Some additional information....

I hope I haven't confused people by describing the walls as perpendicular. I meant perpendicular to the ground, not perpendicular to each other. They do not have to meet at 90 degree angles. The reason I specified perpendicular (to the ground) was that some people who were attempting to solve the problem when it was posed in the paper I read had asked if the walls could be at other than 90 degrees to the ground and such solutions were excluded by the problem poser.

 

[bellenuit]

Sudoku with a Twist

An interesting one for Sudoku fans. It is a standard Sudoku puzzle, except it has no pre-given numbers. Instead, additional information is provided by a sub-puzzle within the larger puzzle. Familiarity with Kakuro certainly helps.



It is a standard Sudoku puzzle in that each 9-cell row (9 in total), each 9-cell column (9 in total) and each 9-cell 3X3 box with a bold outline (9 in total) must contain the digits 1 through 9 without repetition within the row, column or 3X3 box. The numbers within a row, column or 3X3 box can be in any order.

Additionally, cells are grouped together and delineated by dotted lines. Each group has a number at the top leftmost corner, the total for that group. All the cells within a group must add up to the groups total and no number can be repeated within a group.

Like all Sudoku puzzles, there is only one valid solution.

Answers in Spoilers thread please.

 

[bellenuit]

Pi Day

I haven't tried this myself yet, but in honour of today being Pi day, I thought I would get it posted before end of day. Every year has Pi Day on 3.14 (March 14th) as it represents Pi to 2 decimal places in US date format. This year is also once in a century unique because when the year is added in we get Pi to 4 decimal places, 3.1416. Anyway, the problem:



Answers in Spoilers thread please.

 

[bellenuit]

An easy one......



You have a 4 square X 4 square board with 4 pieces: 1, 2, 3 and T. The grey areas represent unoccupied space.

You can move a piece (only one at a time allowed) by sliding (not removing it) on the board to any other unoccupied space, that need not be adjacent, so long as it is only slid through unoccupied space (e.g. you cannot push another piece out of the way).

Your task is to move the big piece T to the bottom right hand corner in just 5 moves (without changing its orientation).

For easy nomenclature, imagine the board as a 4 X 4 grid with rows numbered A, B, C and D and columns numbered 1, 2, 3, 4. For the big piece T, represent where it is moved to by the position of its bottom right hand square, which currently sits in B3.

So to move piece 3 to the bottom left hand square write: 3 to D1.

Answers in Spoilers thread please.

 

[bellenuit]

Anyone for Tennis?

Q1. The men’s singles event at Wimbledon is a knockout tournament with 128 players. How many matches are there in total (extra points for those that can show how they arrived at the answer with the least amount of effort).

Q2. What is the minimum number of times you need to hit the ball with your racket in order to win a set in tennis, assuming that the set goes its full course (e.g. your opponent doesn't forfeit the set for any reason or the set isn't abandoned for any reason like weather etc)?

 

[bellenuit]

An easy one.

Flipping For Your Life

You and a friend have been captured on a desert island ruled by a crazed mathematical despot.

You will be locked in separate cells in the island’s prison, and then set the following task:

Every minute for an hour you will each flip a coin. The flips are simultaneous, and after each flip you will make a prediction as to whether the other person’s flip was heads or tails. You cannot hear the other person's prediction nor use any means to learn of the other's prediction.

So, you both make 60 flips and 60 predictions.

The despot rules that he will kill the two of you if on any one of the 60 predictions you are both correct. (In other words, you both flip, both predict the result of the other person’s flip, and are both right). To escape with your lives at least one of you must predict wrongly each time.

You are given ten minutes to think up a survival strategy before being taken to the cells. Once you are in the cells you cannot communicate with each other, although you are obviously able to see the results of your own flips.

Can you guarantee your survival, and if so, how?

Answers in Spoilers thread please.

 

[bellenuit]

Two puzzles today.

1) Volumes I, II and III of a dictionary are stacked vertically side by side on a shelf (no gaps between them) in left to right order and with their spines visible in the normal way. The thickness of all the pages together in each volume is 6cm, and the thickness of each of the back and front covers of each volume is 0.5cm.

What is the horizontal distance from the first page of Volume I to the final page of Volume III?

2) The following statement is correct

< F is the first and the seventh letter of this sentence.>

Using the sentence above as a model, fill in the gap in the following sentence to make it correct:

<C is the first and the [...] letter of this sentence.>

Answers in Spoilers please...

 

[bellenuit]

I haven't tried these myself yet, so I don't know how difficult they are.

Next in Series

What is the next number in each of the following 3 series?

1) 23, 9, 20, 14, 14, 9, 20, 6, ...

2) 2.1, 3.5, 3.3, 2.3, 1.3, 2.4, 2.5, 2.6, 1.8 ...

3) 1, 2, 9, 12, 70, 89, 97, 102 ...



4) Why might Henry I be an appropriate way to end the following series?

Mary I; George III, Henry III, James II, George IV, Charles I, ...

In relation to question 4, I don't know whether one needs a knowledge of British royalty to solve, but I would assume no.

Answers in Spoiler thread please.

 

[bellenuit]

This looks like a good one.

3 friends (A, B and C) are playing table tennis. They play the usual way: two play at a time, the winner stays on, and the loser waits his/her turn again. At the end of the day, they summarise the number of games that each of them played:

A played 10

B played 15

C played 17.

Who lost the second game and why do you conclude that?

Answers in Spoiler thread please.

 

[bellenuit]

How many Red Balls (only), including the one already there, are needed to make it balance? Worked out logic to be included, not just guesses.


Answers in Spoilers please.