Posted by bob on .
I look at a random time of day at a digital clock (that shows times from 1:00 through 12:59). What is the probability that (ignoring the colon) I see a palindrome such as 8:08? Express your answer as a common fraction.

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Anonymous,
20

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Anonymous,
1/10000000000000000000000

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random bored person,
y'all are soooooooooooooooooooooooooooooo stupid. Anonymous is right

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anounymos,
iT IS 20

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Trueshot,
Actually, it isn't. It's a fraction answer. :)

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Anonymous,
I think it's 19/240

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Anonymous,
its 19/240

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merp,
First, we compute the total number of possible times that can show. There are 12 possible hours, and 60 possible minutes, so the total number of possible times is 12*60 = 720.
Now we compute the number of palindromes. There are 6 palindromes per hour for the nine hours 1 through 9 (1:01, 1:11, 1:21, 1:31, 1:41, 1:51 for example). There is one palindrome per hour from 10 through 12, namely 10:01, 11:11, and 12:21. Hence, the number of palindromes is 6*9 + 3 = 57.
Therefore, the probability that the time is a palindrome is 57/720 = 19/240