Another interesting question.

If you start counting from the thumb of your right hand, on which finger or if thumb, will you have 2009.

An example is also attached to show you how to count.

(Clapping)

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- Mar 21st 2009, 01:51 AMu2_wa[SOLVED] Brainy 3
Another interesting question.

If you start counting from the thumb of your right hand, on which finger or if thumb, will you have 2009.

**An example is also attached to show you how to count.**

(Clapping) - Mar 22nd 2009, 08:54 PMdashed
Im guessing the 4th (ring) finger?

EDIT: nevermind, i just saw the diagram - Mar 24th 2009, 07:18 AMChop Suey
Count the first few numbers on each finger.

Thumb: 1,9,17,...

Index: 2,8,10,16,18,...

Middle: 3,7,11,15,19,...

Ring: 4,6,12,14,20,...

Pinky: 5,13,21,...

The sequences for the thumb, middle, and pinky fingers form an arithmetic progression, each given by $\displaystyle 8n-7$, $\displaystyle 4n-1$, and $\displaystyle 6n-1$, respectively. Since n has to be an integer, we test 2009 for each sequence. The pinky sequence satisfies that condition, therefore you will count 2009 on the pinky.

If the question was asking to find on what finger will you count 2010 initially, then the only choice would be is to finger numbers close 2010 that satisfies the sequences for the thumb or pinky, and then count from there. But this is not applicable if you were to choose a number that satisfies the middle sequence, since you can't tell in what direction is it going. - Mar 25th 2009, 07:53 AMu2_wa
**Thanks**to all who tried!!

The answer is thumb.

Now let me prove.

The equation of pinky that I've calculated is $\displaystyle 5+8(n-1)$

$\displaystyle 5+8(n-1)=2009$, $\displaystyle n=251.5$

n should be an integral number so let**n=251**

$\displaystyle 5+8(250)=2005$$\displaystyle =2005$

Now count from 2005 i.e on pinky to left to 2009 which lands on!!__thumb__

I don't think so this equation $\displaystyle 6n-1$ is of sequence**(Pinky: 5,13,21,...)** - Mar 25th 2009, 08:05 AMChop Suey
Hehe sorry about that, this is what happens when you don't revise your work. But our approaches are the same.

- Mar 25th 2009, 08:16 AMu2_wa