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# RoboThrow

2 replies to this topic

### #1 superprismatic

superprismatic

Not just Prismatic

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Posted 16 May 2012 - 10:25 PM

RoboThrow is a robot which shoots free throw basketball shots.
Once it is set up to shoot, RoboThrow always makes its first
shot and misses its second shot. The probability of RoboThrow
making any subsequent shot depends on its previous shots by
this simple rule: If RoboThrow has made X previous shots and
has missed Y previous shots, it will make the next shot with
probability X/(X+Y) or, equivalently, it will miss it with
probability Y/(X+Y).

What is the probability that RoboThrow will make 75 of its
first 100 shots?
• 0

### #2 plasmid

plasmid

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Posted 17 May 2012 - 03:56 AM

I made a spreadsheet to solve it at first, but after seeing what emerged, I was determined to solve it with equations. This might be a bit wordy, but:
Spoiler for

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Be both a riddler and a guesser in a logic puzzle to the death...
Play Mafia in the Games forum

### #3 superprismatic

superprismatic

Not just Prismatic

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• 1195 posts
• Gender:Male

Posted 17 May 2012 - 08:09 PM

I made a spreadsheet to solve it at first, but after seeing what emerged, I was determined to solve it with equations. This might be a bit wordy, but:

Spoiler for

Nice work, plasmid!
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