## Search found 24 matches

Mon Mar 05, 2018 7:42 pm UTC
Forum: Logic Puzzles
Topic: Nine digit puzzle
Replies: 3
Views: 6729

### Nine digit puzzle

Not too challenging, and fun to solve over a cup of coffee, if you've not seen it before. Question: Arrange the digits 1-9 to make a nine digit number such that the first digit is divisible by one, the first two digits divisible by two, first three digits divisible by three … Solution here: http://d...
Wed Feb 21, 2018 6:19 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1958: "Self-Driving Issues"
Replies: 147
Views: 29657

### Re: 1958: "Self-Driving Issues"

So you're suggesting criminalizing the offense with capital punishment as the sentence?
Wed Feb 21, 2018 6:08 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1958: "Self-Driving Issues"
Replies: 147
Views: 29657

### Re: 1958: "Self-Driving Issues"

There's also the issue that self-driving cars might turn people into jerks
http://datagenetics.com/blog/january42017/index.html

TL;DR - If you know a car is going to stop when you step into the street, why not simply step into the street whenever you like?
Thu Nov 17, 2016 7:27 pm UTC
Forum: Logic Puzzles
Topic: Lost Car Keys
Replies: 1
Views: 3273

### Lost Car Keys

I drive to work, and put my car keys in my pocket. Whenever I sit down in a meeting there is a 20% chance that my car keys might fall out of my pocket (unnoticed). At lunchtime, I reach for my keys and find out they are missing. If I’ve had three sit-down meetings that morning, what is the chance th...
Mon Aug 08, 2016 5:50 pm UTC
Forum: Logic Puzzles
Topic: Sharing secret information publicly
Replies: 27
Views: 6785

### Re: Sharing secret information publicly

You are on the right track, but as you stated, there are some situations, using your strategy, that leaches information to C. You need to come up with a system that does not allow C to learn anything irrespective of what A or B hold.
Mon Aug 08, 2016 4:44 pm UTC
Forum: Logic Puzzles
Topic: Sharing secret information publicly
Replies: 27
Views: 6785

### Sharing secret information publicly

(This puzzle originates from the Moscow Math Olympiad) There are seven cards, numbered sequentially 1-7. The cards are shuffled and dealt (face down) to three people. Player A receives three cards. Player B receives three cards. Player C receives one card. Player A looks at his cards and makes a st...
Fri Apr 29, 2016 9:52 pm UTC
Forum: Logic Puzzles
Topic: Baseball card collecting
Replies: 3
Views: 3146

### Re: Baseball card collecting

Yes, that's the one!

At least it's not a coin weighing problem
Fri Apr 29, 2016 4:50 pm UTC
Forum: Logic Puzzles
Topic: Baseball card collecting
Replies: 3
Views: 3146

### Baseball card collecting

There are 50 baseball cards in a complete set. Cards are purchased in single, sealed, pouches. It's assumed that every card in the set has the same distribution and so the probability of getting any card in the next selected pack is fixed, equal, and constant. What is the expected number of packs yo...
Fri Apr 01, 2016 2:54 pm UTC
Forum: Logic Puzzles
Topic: Drawing Two Bingo Balls
Replies: 3
Views: 3158

### Drawing Two Bingo Balls

A set of bingo balls contains the numbers 1-75.

From a fully shuffled set of bingo balls, you draw one number. Without replacing this ball, you draw a second number. If you win a prize equal to the value of the highest number you draw, what is your expected return?
Sun Feb 21, 2016 9:39 am UTC
Forum: Logic Puzzles
Topic: Two gold nugget puzzle
Replies: 17
Views: 5178

### Two gold nugget puzzle

On a table infront of you are sixteen gold nuggets. You have been told that you can take any two of them as a gift. As is human nature, you wish to take the two heaviest nuggets . The nuggets are all random natural shapes. You are not skilled enough to estimate their individual weights, nor are you ...
Tue Feb 16, 2016 4:12 am UTC
Forum: Logic Puzzles
Topic: Six roll dice game
Replies: 11
Views: 3572

### Re: Six roll dice game

What an awesome and comprehensive answer
Sun Feb 14, 2016 4:54 am UTC
Forum: Logic Puzzles
Topic: d20 rolling puzzle
Replies: 3
Views: 2366

### Re: d20 rolling puzzle

Yes. If the price to re-roll is constant, *and* there is no limit to the number of times you are allowed to re-roll, then the optimal strategy will be a fixed limit stopping strategy. You can use the technique in the blog to find out what this is depending on the cost/dice-range. If there is a limit...
Fri Feb 12, 2016 8:46 pm UTC
Forum: Logic Puzzles
Topic: d20 rolling puzzle
Replies: 3
Views: 2366

### Re: d20 rolling puzzle

This is a great little problem because it's so simple, and you can test your hypothesis with a simple Monte Carlo Simulation.

Once you think you have a good 'strategy' write a few lines of code and test it out by running it a few million times with a random number generator.
Fri Feb 12, 2016 8:44 pm UTC
Forum: Logic Puzzles
Topic: d20 rolling puzzle
Replies: 3
Views: 2366

### d20 rolling puzzle

I have a single (fair and unbiased) d20. We play a game. You roll the die, and can elect to bank, or roll again. If you bank, you walk away with the dollar amount shown on the die, and the game ends. If you elect to re-roll, it costs you \$1 for each new roll. You can re-roll as often as you like. (Y...
Sat Feb 06, 2016 8:35 pm UTC
Forum: Logic Puzzles
Topic: Russian Roulette with multiple cartridges
Replies: 4
Views: 3091

### Russian Roulette with multiple cartridges

You're probably familiar with the vanilla variant of Russian Roulette (where a single round is placed in a six cylinder revolver, it's spun and the trigger pulled). If, instead of one round, two rounds were placed in the revolver, the cylinder spun and the player survives the first trigger pull. Giv...
Thu Feb 04, 2016 9:04 am UTC
Forum: Logic Puzzles
Topic: Six roll dice game
Replies: 11
Views: 3572

### Six roll dice game

A casino offers the following game: You are allowed to roll a regular (fair) die up-to six times. At any time you can "bank" and are paid-out the dollar amount shown on the die (and the game stops). However, there's no going back if you elect to carry on rolling (If you don't "bank&qu...
Fri Jan 15, 2016 9:42 pm UTC
Forum: Logic Puzzles
Topic: Defective Circuit Board Puzzle
Replies: 7
Views: 2964

### Defective Circuit Board Puzzle

Not a super challenging puzzle, but a slightly different spin on the proverbial "balance beam and counterfeit coin" puzzles I have ten circuit boards. Eight are working, but two are defective. My only way to test a board is to use a machine that tests in batches of three. *If there is one ...
Thu Feb 28, 2013 5:32 pm UTC
Forum: Mathematics
Topic: Math Websites
Replies: 125
Views: 176983

### Re: Math Websites

I know it's a self plug*, but if you like reading the works of Martin Gardner (he was a great influence in my life), you might like some of the postings on my blog.

http://www.datagenetics.com/blog.html

*Read a couple of articles before flaming

/\/ick
Sun Aug 19, 2012 7:00 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1096: "Clinically Studied Ingredient"
Replies: 91
Views: 23749

### Re: 1096: "Clinically Studied Ingredient"

"Real chocolate flavor"
Sun May 22, 2011 3:19 pm UTC
Forum: News & Articles
Topic: Everything Must GO? Several months until the Rapture?
Replies: 301
Views: 29495

### Re: Everything Must GO! One Week until the Rapture!

I'm not sure about Rapture, but facebook just passed 666 million registrations Worldwide http://www.datagenetics.com/blog/may22011/index.html so, 1 in 10 people on earth are on facebook. What with the owner of facebook being a Jew, I'm starting to think that we are part of a world domination conspi...
Sun May 22, 2011 6:29 am UTC
Forum: News & Articles
Topic: Everything Must GO? Several months until the Rapture?
Replies: 301
Views: 29495

### Re: Everything Must GO! One Week until the Rapture!

I'm not sure about Rapture, but facebook just passed 666 million registrations Worldwide

http://www.datagenetics.com/blog/may22011/index.html
Fri Apr 15, 2011 6:13 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 0886: "Craigslist Apartments"
Replies: 137
Views: 47607

### Re: 0886: "Craigslist Apartments"

I visited Pripyat last year. It's a spooky place, but also cool to visit in a geeky way.
Here are some pictures
Fri Jan 28, 2011 11:22 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 0853: "Consecutive Vowels"
Replies: 159
Views: 42472

### Re: 0852: "Consecutive Vowels"

Don't forget about "Euouae"
http://en.wikipedia.org/wiki/Euouae
Sat Jan 01, 2011 1:16 am UTC
Forum: News & Articles
Topic: FaceBook and 600 million users ... ?
Replies: 0
Views: 956

### FaceBook and 600 million users ... ?

It looks like facebook will finish 2010 with 575 million registered users: [link removed] This is a slight slow down in the rate of growth, but still very impressive. Anyone care to guess when they will announce 600 million registrations? Yeah, don't come here just to post your own stuff. My bad for...

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