Thursday, September 25, 2008

Round 280

Date Released: September 25th, 2008.
Date Rewarded: October 2nd, 2008.

A Chomby was walking down a path one day when Jhudora appeared in front of it. "Solve this puzzle, and you may pass," she said.

Suppose a1 is the first digit (after the decimal point) of Pi, a2 is the second digit, and so on...

What would the following formula equal:
(a1 - a2) * (a2 - a3) * (a3 - a4) * ... * (a99 - a100)

What is the answer?

Prize


Flatfruit Table

Click to show/hide hints

The numerical value of PI truncated to 100 decimal places [1] is:

3.1415926535 8979323846 2643383279 5028841971 6939937510 5820974944 5923078164 0628620899 8628034825 3421170679

We notice that a24 = a25 = 3. Therefore the formula equal to:
(a1 - a2) * (a2 - a3) * ... * (a23 - a24) * 0 * (a25 - a26) * ... * (a99 - a100) = 0

There are several other pairs of consecutive digits that are the same. The answer is 0.

Results: 6249 people guessed the correct answer earning themselves 321 NP each.

References:
[1] Decimal expansion of PI

13 comments:

Danielle said...

It took me a bit to see the easy way, but I got it. I actually figured this one out before checking here. ^_^

Katie said...

Yeah, I figured it out before coming here. I went through like the first 50 digits then was like, "Wait, the zero!" Haha.

LUANNA said...

Someone mail me a hint. I am confused...

moonbeamer@hotmail.com

THANKIES

neohelper said...

For the record, the 59th and 60st digit are 4, not 8. Doesn't change a thing though.

mohd_azim said...

What is the answer?

iPanda said...

luanna, the 59th and 60th digit are 4 and 4. 4*4=? Then, take the next digit, 5. ?*5=?, and then ?*9=?.

Sorry for the question marks, but they would give away the answer. Really, it is very simple. Just do the math.

LUANNA said...

So what should I do from there?

Zantunara said...

ipanda are you taking the number after subtracting and then multiplying? I don't see any subtraction in the clue that you are giving. Could cause a bit of confusion

theCrew said...

the clue lennysolver gave was pretty obvious, a^59-a^60 = 0

so its (a^58-a^59)*0*(a^59-a^60)and blah blah blah, if you don't get it alr. then gg lol

Happy said...

If you still don't know the answer, email me.

Xiaohangd@yahoo.ca

Wow, if I get this one right, it'll be my first one ever!

JirachiNite said...

Ah, I get it! Took me a while, but I understand it now! =D

natasha said...

i dont get it....

SONJA ! said...

I won (a meagre) 231NP..