Quote:
Originally Posted by aceplace57
Cracked has an article on mentalist tricks.
The one guessing a person's age has me stumped. The algorithm they give works.
http://s3.crackedcdn.com/phpimages/p.../568309_v1.jpg
Age 32
3 (1st digit) x 5 = 15 + 3 = 18 x 2 = 36 + 2 (2nd number in age) = 38
The person says 38 and you tell them they are 32. By subtracting 6. ***applause***

First digit times five... well in the two digit number, thats the number of tens, and the number of ones is being added on again later, so "times five" is really "divide by two".. 3 times five is 30 divide two... see ?
So then add 3, and then double . You can move the 3 to be after the double.. well the "add three" was doubled , so thats really add six.. which is then cancelled by subtract 6.
Then add in the ones column, and subtract six ...
basically the add 6 is disguised as "halve, add 3 and double", but the halve is disguised as tens column times 5...