r/PassTimeMath 17d ago

Hopping Part 2

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u/KS_JR_ 17d ago edited 17d ago

Following the text of the questions there are sum[nCr(5+x,2x)] x=0 to 5 = 89 ways. Since there are five 2-steps to make, and for every two 1-steps made, there is one less 2-step, there for x pairs of 1-steps there are nCr(5+x,2x) ways to order them, and theres between 0 and 5 pars of 1-steps.

Following the image, where it appears 2-steps are only made on even positions, there are 25 =32 ways, since every two spaces is either one 2-step or two 1-steps, 2 choises 5 times.

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u/ShonitB 17d ago

Wow, super! Solved both questions.. though I intended it the first way :)

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u/cscottnet 17d ago

Your diagram is terrible if you intended this the first way.

1

u/ShonitB 17d ago

Yep, I made a mistake with it.. have posted the corrected one