### Brain Teasers

# Chessboard

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

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?

### Answer

32/64 or 1/2Hide Answer Show Answer

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## Comments

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

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)

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.

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

Duh! Sorry - Cath already said that!

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.

there are just too many answer that depend on info we don't have

THE CHICKS DONT EVEN KNOW THE NAME OF MY BAND

my answer is 31/62.

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)

The *and* was changed to *or* which makes more sense. (32/64 or 1/2)

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