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# harey

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• Birthday February 26

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1. ## Silver dollar

There is a strip of N (N>13) squares. In the middle is the SILVER DOLLAR. Two players alternatively place a penny on an empty square. Then, at each turn, a player must: - move one coin one or more squares to the left, observing: - the coin cannot move out of the strip - the coin cannot jump on another coin - the coin cannot jump over another coin - or - - pocket the leftmost coin Best strategy?
2. ## Harder hats on deathrow version

@Plasmid I translated your notation into mine, as far as we are gone, we have same results (excepted some doublets). I thought about interpolation, too, but I did not go this way estimating there is not enough data.
3. ## Harder hats on deathrow version

I fear there is no solution.
4. ## Climbing Stairs

Same as rocdocmac Combinatorics:
5. ## Liars and truthtellers one again

Thanks for finding the problem. I was so sure that if X contradicts Y, they must be in different categories - it did not occur to me that can be both liars.
6. ## Liars and truthtellers one again

Do not worry, on my first attempt, I did not manage it to write it clearly enough that I myself could read and understand it. When you asked your question, I checked my solution written about a year ago and wondered whether it would not be easier to start from the beginning. I have rewritten it and found a kind of notation: P.S. Can someone change in the title ONE in ONCE? Thanks in advance.

8. ## Liars and truthtellers one again

On an island, every statement is true if the islander is aged less than L and false if he is at least L years old. Find their ages. [1] A: "B is more than 20 years old." [2] B: "C is more than 18 years old." [3] C: "D is less than 22 years old." [4] D: "E is not 17 years old." [5] E: "A is more than 21 years old." [6] A: "D is more than 16 years old." [7] B: "E is less than 20 years old." [8] C: "A is 19 years old." [9] D: "B is 20 years old." [A] E: "C is less than 18 years old."
9. ## The Dyer's Puzzle

There be sixty-and-four flowers-de-luce (in a grid 8x8), and the riddle is to show how I may remove six of these so that there may yet be an even number of the flowers in every row and every column. I am not able to remove 6 of them: interactive version What am I missing? Solution. that does not help me. I got it now, to late to delete.

I did some research... At first, the drawing Nick made is somewhat confusing. What he calls "forward force" should be "thrust" and what he calls "thrust" should be "drag". Just google "drag thrust weight lift". If thrust=drag and lift=weight, the plane will fly at constant speed at constant height (plenty of pages). Now, the question is how much thrust we need to generate lift=weight (or a little better). On the end of the article https://en.wikipedia.org/wiki/Lift-to-drag_ratio, there is a table: latest air-crafts have a coefficient over 19.
11. ## Who lies and who tells the truth?

I fear there are multiple solutions. Babysnoot is correct, just the only reason to proclaim Jester truthteller is that there is no further contradiction in the system. For Bear=truthteller, Drummer=liar, others=mix (it does not matter whether what they say is true or false), there is no contradiction in the system, neither. Does someone agree?
12. ## Finding a fiver

A table with English words by the set of all combinations (with repetition) of 7 letters. However, even with some tricks like sorting the letters, I do not think my computer would give me the answer overnight. Remains the Monte-Carlo method. However, I am pretty sure it is not the expected answer. A hint?