Posted by bob on Thursday, November 15, 2012 at 10:28am.
20
1/10000000000000000000000
y'all are soooooooooooooooooooooooooooooo stupid. Anonymous is right
iT IS 20
Actually, it isn't. It's a fraction answer. :)
I think it's 19/240
its 19/240
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