FILE No.60Unsolved
At the celebration of the "Leap Day Club", open only to people born on February 29, a commemorative gold coin meant for members alone was taken. One of four people is an outsider posing as a member.
Most people celebrate on February 28 or March 1 and add a year every year. This club insists on February 29. In the club, the number of times February 29 has actually come around is called a member’s "club age". The year of birth counts as 0 and is not counted. The time is October 2026.
The receptionist asked each of the four for their year of birth and their club age.
Who is the impostor? Look closely at the evidence.
If you get stuck, open the hints one at a time, in order.
A real member knows their own club age exactly.
Check, one by one, whether each statement matches the birth year on the roster.
The next February 29 after 1996 is in 2000. What about 2000?
Who is the impostor? Look closely at the evidence.
Choose the answer closest to the truth.
Kawashima
The answer is: Kawashima.
A real member knows their own club age exactly. Count from the year of birth on the roster and check each statement.
Ono (born 2004): 2008, 2012, 2016, 2020, 2024, so 5. Kitamura (born 2008): 2012, 2016, 2020, 2024, so 4. Morishita (born 2012): 2016, 2020, 2024, so 3. These three match what they said.
Kawashima (born 1996): 2000, 2004, 2008, 2012, 2016, 2020, 2024, so 7. But Kawashima said 6.
2000 is divisible by 100, but it is also divisible by 400, so it is a leap year and February 29 did come around. Kawashima’s "6" skipped 2000. A real member would not get their own number wrong, so Kawashima is the outsider who knew only the birth year on the roster.
Note that if you believe 2000 is not a leap year, all four statements match the roster. That contradicts the condition that exactly one is lying, which is the cue to think again.
People think "2000 is a multiple of 100, so it is not a leap year".
The cases on this site are fictional puzzles created for entertainment. Any resemblance to real people, organizations or events is coincidental.
© Unsolved Files
