Case 183
The Missing Ledger
A confidential ledger disappeared from the office.
Rule: exactly one suspect is guilty. The guilty suspect lies. Every innocent suspect tells the truth.
Riley
“Either Kendall or Logan is guilty.”
Drew
“Kendall and Logan are both innocent.”
Kendall
“Frankie is innocent.”
Frankie
“Drew and Logan are both innocent.”
Logan
“Drew and Kendall are both innocent.”
Who is guilty?
Solution: Riley
If Riley is guilty, Riley's statement is false and every other statement is true. Testing the other suspects creates at least one contradiction.