Log in

Mental Workout's Journal
[Most Recent Entries] [Calendar View] [Friends]

Below are the 20 most recent journal entries recorded in Mental Workout's LiveJournal:

[ << Previous 20 ]
Wednesday, April 27th, 2011
7:16 pm
U2 Bridge Crossing
My mom got this puzzle:

U2 has a concert that starts in just 17 minutes and all of the
band members must all cross a bridge to get there. The four men
begin on the same side of the bridge and you must help them to
get across to the other side.

Due the age of the bridge, a maximum of two people can cross at
one time. To make matters worse, it is night-time and there is
only one torch. The torch is always required when crossing the
bridge and the torch must be walked back and forth, it cannot be
thrown, etc. Each band member walks at a different speed and a
pair must walk together at the rate of the slower man:

Bono takes 1 minute to cross
Edge takes 2 minutes to cross
Adam takes 5 minutes to cross
Larry takes 10 minutes to cross

For example, if Bono and Larry walk across first, it takes them
10 minutes to cross. If Bono then returns with the torch, a
total of 11 minutes will have passed. There is no trick behind
this, it is the simple movement of resources in the appropriate

I'm guessing the question is how do you get them all across and what is the shortest amount of time that can be gotten to get them all across?
Wednesday, November 17th, 2010
10:16 pm
The Superhero Riddle
Try my superhero riddle! newarrior knows the answer. zyxwvut figured it out. No one else has got it in all this time.

You don’t have to know anything about the superheros other than what they look like. Some helpful pictures follow!

The Premise: Most mainstream superheros can be placed into one of four categories.

Category 1
Green Lantern:

More of Category 1Collapse )

Category 2

More of Category 2Collapse )

Category 3
(Interesting to Note: Markedly few characters seem to fit into this category. Deadman and Nite Owl are just about the only two heroes I've found.)

See Category 3Collapse )

Category 4

More of Category 4Collapse )

The Challenge: Figure out how all these characters are categorized!

As before, I'll take any question calling for a yes or no.

Additional InformationCollapse )
Friday, April 23rd, 2010
7:13 am
The Riddle of Brightest Day and Blackest Night
This is a riddle about comic book superheros. So far no one has solved it.

You can still solve it, though, if you do not read comics. You may have to do internet searches on certain names. You do not have to be an expert on the characters.

I can divide most superheros into four related categories.

THE RIDDLE: How are the characters categorized? You can figure it out by studying the lists.

The Four Category ListsCollapse )


*I'll answer any query that calls for a yes or a no.

*Name a superhero and I'll tell which of the four categories that character belongs in. In some cases, characters will not fit into any of them.

Happy riddling!
Monday, May 4th, 2009
11:46 am
Most Annoying Songs - Please Come Vote!
Please come vote for your top five most annoying songs at this poll! I don't have enough of a data set yet to complete a new entry about the winners! I know that people are anxious to see the results.

The poll is located here:
Friday, October 10th, 2008
11:31 pm
I know, a lot of these are old riddles. Just some I collected today while I was working.

Two brothers we are
great burdens we bear,
all day we're bitterly pressed
Yet this will I say
We are full all day
and empty when we go to rest

What has roots as nobody sees,
Is taller than trees,
Up, up it goes,
And yet never grows?

A box without hinges, key, or lid,
Yet golden treasure inside is hid.

As light as a feather, but you can't hold it for ten minutes.

Has a mouth but does not speak,
has a bed but never sleeps.

Runs smoother than any rhyme,
loves to fall but cannot climb!

You feed it, it lives,
you give it something to drink, it dies.

I go around in circles,
But always straight ahead
Never complain,
No matter where I am led.

My life can be measured in hours,
I serve by being devoured.
Thin, I am quick
Fat, I am slow
Wind is my foe.

I have legs but walk not
A strong back but work not
Two good arms but reach not
A seat but sit and tarry not

I run through hills;
I veer around mountains.
I leap over rivers
and crawl through the forests.
Step out your door to find me.
Saturday, August 23rd, 2008
6:30 pm
Brain Teasers!
Teaser the First

A man worked for a high-security institution, and one day he went in to work only to find that he could not log in to his computer terminal. His password wouldn't work. Then he remembered that the passwords are reset every month for security purposes. So he went to his boss and they had this conversation:
Man-"Hey boss, my password is out of date."
Boss-"Yes, that's right. The password is different, but if you listen carefully you should be able to figure out the new one: It has the same amount of letters as your old password, but only four of the letters are the same."
Man: "Thanks boss."
With that, he went and correctly logged into his station.
What was the new password?
BONUS: What was his old password?

Teaser the Second

This is an unusual paragraph. I'm curious how quickly you can find out what is so unusual about it? It looks so plain you would think nothing was wrong with it! In fact, nothing is wrong with it! It is unusual though. Study it, and think about it, but you still may not find anything odd. But if you work at it a bit, you might find out! Try to do so without any coaching!

Teaser the Third

Heart of Darkness,
Coat of Grain,
Was once alive,
Now feels no pain,
Never walks, but
Leaves a Trail.
Circle head and pointed tail.
Grows shorter as the day goes on-
Its waistline is a hexagon.

What is it?

Teaser the Fourth

While exploring the wilds of Canada, Wild Man Dave was captured by hostile wood fairies. Brad, the powerful chief of the fairies told him he could make one final statement which would determine how he would die. If the statement he made was false, he would be boiled in water. If the statement were true, he would be fried in oil. Wild Man Dave found neither of this options too his liking, so he made a statement that got him out of this seemingly impossible situation. What is the one statement he could have made

Teaser the Fifth

Four members of a band are walking to a night concert. They decide to take a shortcut, but must cross a bridge. Luckily they have one flashlight. Because of the varying size of their instruments, it takes each member a different amount of time to cross the bridge - it takes the first person one minute, the second person two minutes, the third person five minutes and the fourth person ten minutes. They must cross the bridge in pairs, travelling at the slower speed so if the one minute person went with the ten minute person, it would take a total of ten minutes. Since there is only one flashlight, one person must come back across the bridge, then another pair can cross. They only have 17 minutes to cross the bridge and still get to the concert on time. What order should they cross to get everyone across and get to the concert?

x-posted to kagomeshuko and mental_workout
Sunday, July 6th, 2008
9:13 pm
Riddle time
Anyway, there was a riddle in today's bulletin at St. Michael's.

The words were a little bit different, but it is about the same as this one:

God made Adam out of the dust,
But thought it best to make me first;
So I was made before the man,
According to God's Holy plan.
My whole body God made complete
Without arms or hands or feet.
My ways and acts did God control,
But in my body He placed no soul.
A living being I became,
And Adam gave to me a name.
Then from his presence I withdrew,
For this man Adam I never knew.
All my Maker's laws I do obey,
And from these laws I never stray.
Thousands of me go in fear,
But seldom on the earth appear.
Later, for a purpose God did see,
He placed a living soul in me.
But that soul of mine God had to claim,
And from me took it back again.
And when this soul from me had fled,
I was the same as when first made;
Without arms, legs, feet, or soul,
I travel on from pole to pole.
My labors are from day to night,
And to men I once furnished light.
Thousands of people both young and old,
Did by my death bright lights behold.
No right or wrong can I conceive;
The Bible and it's teachings I can't believe.
The fear of death doesn't trouble me;
Pure happiness I will never see.
And up in Heaven I can never go,
Nor in the grave or Hell below.
So get your Bible and read with care;
You'll find my name recorded there.

Yes, I know the answer. Do you know the answer?
Sunday, February 3rd, 2008
12:45 pm
Okay, I tried to solve this puzzle that I made up at amphibolous's Feast, and I was almost convinced that it wasn't possible. So I tried to prove that it was unsolvable... and I wound up solving it. Can you? (For many of you on my flist, this challenge will probably be a piece of cake.)

In a four-by-four grid, arrange four As, four Bs, four Cs, and four Ds, so that each column and each row has exactly one of each. Basically, they need to be a Latin square. Then, in the same grid, arrange four 1s, four 2s, four 3s, and four 4s, so that each column and each row has exactly one of each and so that no cell of the grid contains the same letter-number combination as any other cell of the grid.

You can work this puzzle out physically with sixteen playing cards, magic lands, or squares of construction paper and sixteen meeples, glass bead counters, or bottle caps.

My next question is "for what nxn is this challenge solvable?" It's clearly impossible for 2x2, so I conjecture it's solvable for n 3 and greater.
Thursday, January 10th, 2008
4:52 pm
Keyboard speak
Hello. First time to this community. I infrequently post homemade brainteasers on my journal and finally remembered to do an interest search on brainteasers. Here's my latest.

When I take the digits on a keyboard to resemble letters, I see (which may not be what the kid's l33t speak translates):
1 = I
2 = Z
3 = E
4 = A
5 = S
6,9 = G,g
7 = T
8 = B
0 = O
Or to sum up, nine different letters:
I, Z, E, A, S, G, T, B, O

How many six letter English words can you make with them (no plurals, no repeating a letter)?

I've found four so far and two more have been found.
See the answers in the comments here.

Current Mood: chipper
Tuesday, December 4th, 2007
7:48 pm
puzzled gear
Couple of weeks ago, I wanted to get a set of mugs with puzzles/riddles on them, to set out for guests. Looked around online, didn't find anything suitable, so figured I'd make something on a design-it-yourself site.

Then I thought others might be interested, so I made a whole bunch here.

Think this would interest people? Any ideas/suggestions? I could slap the same thing on shirts/bumper stickers/whatever, but not sure anyone would care.

(I also posted this to problemaday, sorry if you're seeing it twice.)
Tuesday, October 16th, 2007
5:47 pm
Solve it
11:49 am: Figure it out!
In a cabin in the woods rescue workers found a dead body.
The cabin was locked from the inside.( Windows and doors unbroken)
There were no footprints in the 2 day old snow around the cabin.
The person had been dead no more than 6 hours.
The cause of death was a blow to the head.
The dead person was strapped to a padded seat, but the hands were free.

You get to ask three questions to help you solve this.

If you figure this out--offer me a word puzzle.
Friday, September 14th, 2007
10:24 am
A man is driving. Every few minutes, he briefly tilts his head in an uncomfortable manner.

Update: solved by luckykaa - solution.
Thursday, September 13th, 2007
12:27 pm
A woman shoots her husband, dunks him for five minutes, and hangs him. Yet, one hour later, she is seen eating lunch with him at a restaurant. How can this be?

A man is sentenced to death. He is given three choices: Be put in a room full of fire, be put in a room full of angry terrorists, or be put in a room full of lions who haven't been fed for three years. Which should he choose?
Wednesday, July 4th, 2007
1:14 am
Hi, I made this puzzle. It's a Tentai Show, a puzzle type that is frequently made by Nikoli.

Rules as I would state them:
Each circle is the center of a shape with 180 degree rotational symmetry. Each shape contains exactly one circle. There are no lines which do not form the border of a shape. Shapes may enclose other shapes. Color the black-circle shapes for a PICTURE SUPRISE.

Official rules and example from Nikoli

Two sizes for your monitor resolution convenience:

Please let me know what you think of it! I'd also like to know if anyone has any suggestions for other communities or forums to post this in. I have been working on several puzzles lately and don't know who to show them to.
Tuesday, May 1st, 2007
8:32 pm
ok, one more... Y/N/IR
Two men are locked in the trunk of a car overnight. When they are found and released in the morning, one man is alive and one man is dead.
Sunday, April 29th, 2007
1:19 pm
Revolving Door Solution
Here's my (probably not the only) correct solution the question about revolving doors I posted earlier in http://community.livejournal.com/mental_workout/17764.html .

Solution under LJ CutCollapse )
Saturday, April 28th, 2007
4:37 pm
another Y/N/Ir
Ok, that last one was quick, so here's another.

A girl has pet birds. She lets them fly around in her backyard, but whenever it's raining, she locks them up in cages, brings them inside, and locks all the doors.

What is the reason for this behavior?
10:35 am
Two men go to a restaurant. They sit down and order identical soft drinks. When the soft drinks arrive, one man drinks his quickly and the other drinks his slowly. While still at the restaurant, the man who drank his drink slowly dies. Why?
Wednesday, April 25th, 2007
1:11 am
How do you modify a revolving door so that people may enter the revolving chamber as one normally enters a revolving door but so that they are unable to exit the chamber (even by how they entered), although able to revolve in it?

The revolving door may not have more than one state. That is, you cannot install a sensor that closes the entrance when somebody enters. Theoretically, as many people as can fit should be able to enter the revolving door even after the first people have revolved numerous times without exit.

You may not use adhesives or magnets to prevent revolvers from separating themselves from the revolving door.

ETA:In other words, you may not incapacitate the victims or use injury as your means to keep them from escaping. They must be able to keep going around as long as they choose to (and longer if other people are pushing the revolver.)
Sunday, April 22nd, 2007
10:55 pm
another mental workout!
What belongs to you but is mostly used by others?
[ << Previous 20 ]
About LiveJournal.com