# Twinhelix

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## Twinhelix's Activity

1. Twinhelix added a post in a topic

Personally I agree with this answer...

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2. Twinhelix added a topic in New Logic/Math Puzzles

If you choose an answer at random, what is the chance you will get it correct?

a) 25%
b) 50%
c) 60%
d) 25%
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3. Twinhelix added a post in a topic

Can you show working?
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4. Twinhelix added a post in a topic

Yes your second interpretation is right. So basically what it is saying is that there exists a number n, where any two people have greeted n people in common. Does that make sense?
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5. Twinhelix added a post in a topic

Hey, there's a +1 at the end of that formula, double check the question, I wouldn't ask something that straight forward
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6. Twinhelix added a post in a topic

At a meeting of 12k people, each person exchanges greetings with exactly 3k + 6 others. For any two people, the number who exchange greetings with both is always the same. How many people were at this meeting?

@Silver Surfer, 12k is not 12,000. k is a constant here that you need to find
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7. Twinhelix added a post in a topic

Ok I pick the elements 5 12 15?
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8. Twinhelix added a post in a topic

Okay imagine there's bridges where roads would cross
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9. Twinhelix added a topic in New Logic/Math Puzzles

Alright, here is round 5 for the Talent Search Questions. Hope you guys are enjoying them Will try find some good questions for ya'll

*** REMEMBER TO SHOW ALL WORKING!! ***

Here we go :

1. Prove that 11 * (14^n) + 1 is never prime.

2. Let n, k be positive integers such that n is not divisible by 3, and k>=n. Prove that there is a positive integer m which is divisible by n, and the sum of its digits in decimal representation is k.

3. M is a subset of {1, 2, ..., 15} such that the product of any three distinct elements of M is not a square. Determine the maximum number of elements in M.

4. At a meeting of 12k people, each person exchanges greetings with exactly 3k + 6 others. For any two people, the number who exchange greetings with both is always the same. How many people were at this meeting?

5. A game is played between two players who move alternatively. Initially there are an arbitrary number of matchsticks in each of two piles. Each move is one of the following three types:

(i) A withdraw of any number of matchsticks from the first pile;
(ii) A withdraw of any number of matchsticks from the second pile;
(iii) A withdraw of the same number of matchsticks from both piles.

Winner is the person who takes the last matchstick. Given best play from both sides, find all winning positions (for the player who has just played).

GOOOOOOOOOOOOOOOOOOO!
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10. Twinhelix added a post in a topic

If you wanna learn java, hmmmm, I don't know about any good website, I'll try look for some online tutorials that I think are good. But do you know any other object orientated programming languages?
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11. Twinhelix added a post in a topic

Hey your assumptions are correct. However I think your approach is not the best.

Here's a hint:

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12. Twinhelix added a post in a topic

No sorry they do not cross.
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13. Twinhelix added a post in a topic

here

Sorry the upload of the image failed.
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14. Twinhelix added a post in a topic

Yes that is indeed correct!

Regarding the game show question, I wrote a simulation and ran it to check the chances, here they are:
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15. Twinhelix added a post in a topic

2 Still needs to be solved!! GOGOGO
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