View Full Version : Challenging math brain teaser


Abi
06-20-15, 11:46 AM
Took me about 10 mins with pen n paper.

Detective Hound was inspecting the scene of the crime. The 50-year-old victim, Joe, had been poisoned by a candy containing cyanide. Some unpoisoned candies were found on a tablle near Joe's body. This murder was highly suspicious, because Joe had just gotten off a 2-yr jail sentence.

Hound was very puzzled, because he had recently come across three similar murders, none of which had been solved. Jeff, 30, had gotten off a 10-yr sentence a few weeks ago. The next day, he had been found murdered in the same fashion as Joe, but in his case only 3 candies were left on the table. John, 46, was found with 5 candies the day after a 4-yr sentence had been turned over a week ago. Jim, 35, had gotten off a 5-yr sentence a few days ago, only to be found dead with 6 candies yesterday.

Hound puzzled over these cases for days, and then -boom- it hit him. There was a pattern in these murders!

Each suspect ate a candy before they died.
Life expectancy when the murders were committed was 70 years.

(It was also curious that many criminals had been let off their sentences too, but had not been killed. 23, in fact, had gotten off.)


HOW MANY CANDIES WERE FOUND AT THE SITE OF JOE'S MURDER?

dvdnvwls
06-20-15, 12:12 PM
9 candies left?

Abi
06-20-15, 12:19 PM
Wow. Yes!

Summary of calculations please.

dvdnvwls
06-20-15, 12:28 PM
I used:
Let r = remaining life expectancy (i.e. 70 minus current age)
Let s = sentence length
Let c = candies left

c * s = r - s

Abi
06-20-15, 12:29 PM
Nice :)

dvdnvwls
06-20-15, 12:33 PM
What do the x's mean? I don't feel like kissing anyone just yet this morning. ;)

Abi
06-20-15, 12:35 PM
Hey David,

What's your educational background, apart from music?

dvdnvwls
06-20-15, 12:36 PM
Most important thing I did to solve it was to suspend common sense before beginning. :)

Abi
06-20-15, 12:36 PM
I was confirming your method. I used a different method .

dvdnvwls
06-20-15, 12:37 PM
Hey David,

What's your educational background, apart from music?

Apart from music? High school.

Abi
06-20-15, 12:53 PM
Nice :)

Abi
06-20-15, 12:54 PM
I used probability and what not :o

dvdnvwls
06-20-15, 02:13 PM
I don't know any what not :) , but my real method was to put the data into a table and scan for too-good-to-be-true coincidences.