Warhawk Puzzler
Able was I ere I saw Elba . . .
Math Department
Issue date: 4/27/09 Section: Features
Able was I ere I saw Elba . . .
is a well-known palindrome. This week's puzzle concerns palindrome years. A palindrome year is a year that remains the same if the digits are reversed. In fact, those of us born on or before 1991 have lived in two palindrome years - 1991 and 2002. Big deal, you say? The previous occurrence of two palindromic years in one person's lifetime was over a thousand years ago - the years 999 and 1001.
How many palindrome years were there from (and including) year 1 A.D. to the year 2000?
Note that this includes 1-digit palindrome years (i.e. 5), 2-digit palindrome years (i.e. 77), 3-digit palindrome years (i.e. 404) and 4-digit palindrome years (i.e. 1991).
**********
Four people come to a river in the night. There is a narrow bridge, but it can only hold two people at a time. Because it's night, the flashlight has to be used when crossing the bridge. Person A can cross the bridge in 1 minute, B in 2 minutes, C in 5 minutes, and D in 8 minutes. When two people cross the bridge together, they must move at the slower person's pace. The question is, how can they all get across the bridge in 15 minutes or less?
Solution: A and B cross (2 min). A returns (1 min). C and D cross (8 min). B returns (2 min). A and B cross (2 min).
is a well-known palindrome. This week's puzzle concerns palindrome years. A palindrome year is a year that remains the same if the digits are reversed. In fact, those of us born on or before 1991 have lived in two palindrome years - 1991 and 2002. Big deal, you say? The previous occurrence of two palindromic years in one person's lifetime was over a thousand years ago - the years 999 and 1001.
How many palindrome years were there from (and including) year 1 A.D. to the year 2000?
Note that this includes 1-digit palindrome years (i.e. 5), 2-digit palindrome years (i.e. 77), 3-digit palindrome years (i.e. 404) and 4-digit palindrome years (i.e. 1991).
**********
Four people come to a river in the night. There is a narrow bridge, but it can only hold two people at a time. Because it's night, the flashlight has to be used when crossing the bridge. Person A can cross the bridge in 1 minute, B in 2 minutes, C in 5 minutes, and D in 8 minutes. When two people cross the bridge together, they must move at the slower person's pace. The question is, how can they all get across the bridge in 15 minutes or less?
Solution: A and B cross (2 min). A returns (1 min). C and D cross (8 min). B returns (2 min). A and B cross (2 min).
Be the first to comment on this story