1988 AJHSME Problems/Problem 25
Revision as of 15:41, 21 April 2009 by 5849206328x (talk | contribs) (New page: ==Problem== A '''palindrome''' is a whole number that reads the same forwards and backwards. If one neglects the colon, certain times displayed on a digital watch are palindromes. Three...)
Problem
A palindrome is a whole number that reads the same forwards and backwards. If one neglects the colon, certain times displayed on a digital watch are palindromes. Three examples are: , , and . How many times during a -hour period will be palindromes?
Solution
From to , the times will be of the form . There are choices for and choices for , so there are times in this period.
From to , the minutes are already determined, so there are only times in this case.
In total, there are palindromic times.