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Probability puzzles require you to weigh all the possibilities and pick the most likely outcome.


Puzzle ID:#5051
Fun:** (2)
Difficulty:*** (2.15)
Submitted By:Smart***
Corrected By:MarcM1098




If a chessboard has 64 squares and you roll a die across white, what is the probability of the die landing on a white square?

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Jul 08, 2002

This is wrong, I was going to submit a similar puzzle but I thoguht it might have been too hard. Sure we'll see.
Jul 08, 2002

If you are throwing darts the answer is 1/2 but because the dice has some dimensions, there is a larger chance of some part of it landing in a white square. For example if the board has squares of size 2 square cm, and the dice is 4 square centimeters, then the probability is 1 that it will land on a white square. (As you reeduce the size of the dice, the probability will tend to 1/2)
Dec 03, 2002

but then how did he get 32/64.5???? the die is (supposedly) smaller than one square. i don't see where rolling it across a white square matters. also, you say it is bigger so it has a bigger chance of landing on white (or something to that effect) but it would also have a bigger chance of landing on black, so it would still fall even. If somebody can clue me in, that would be great. also, i think it would help to explain your answer, rather than just stating it.
Mar 14, 2003

Firstly I don't understand the phrase "roll across white". Does this mean it rolls out of the white corner square into any other? Then the answer would be 31 in 64. If by landing on a white square you mean any part of the die touches a white square (ie not wholly inside a black) then it depends on the relative sizes of the dice and the squares. If the die was bigger than 1 square, it would always land with some part on a white square? ie P = 1. If the die were infinitely small, it would almost always land either within a black or a white square P = 0.5
Mar 14, 2003

Duh! Sorry - Cath already said that!
Apr 01, 2005

At first read, this just sounds really stupid. Whoever approves these things being posted should require that the proof be supplied (i.e., explain how you got the answer). Now that I've read it over a couple times, I still think it's stupid.
Oct 12, 2005

there are just too many answer that depend on info we don't have
Nov 13, 2005

Mar 31, 2006

my answer is 31/62.
Jan 24, 2007

The original answer was "32 over 64 *and* a half", see speedyg1000's comment.
The *and* was changed to *or* which makes more sense. (32/64 or 1/2)

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