GeekDad Puzzle of the Week: Tortoise Soup – Solution

Reading Time: 2 minutes

800pxlonesome_george_pinta_giant_to800pxlonesome_george_pinta_giant_toCongratulations to Martin Silbiger who cracked the Beagle’s case of herpicide and was selected among correct answers for a $50 gift code to ThinkGeek. Check the solution after the jump for your code for $10 off of your next $30 purchase at ThinkGeek.

During slow periods on the HMS Beagle, Augustus, Bartholomew, and Clements often remarked that despite its "antideluvian" appearance, the large tortoise that the young Darwin had brought on board looked rather tasty and might make a "refined and splendid soup." Naturally, they were suspected and confronted when the poor creature was found hacked in pieces with a cleaver. Investigations by Captain FitzRoy concluded that one of the three is certainly guilty. They have each offered statements as follows:

Augustus: 1) I have not seen nor had any contact with the tortoise for a week before the unfortunate carcass was found. 2) Everything that
Bartholomew says is true. 3) Everything that Clements says is true.

Bartholomew: 1) I have never handled a cleaver. 2) Everything Augustus says is false. 3) Everything Clements says is false.

Clements: 1) Augustus was seen with the tortoise just before its cut up body was found. 2) Bartholomew has handled a cleaver. 3) I have for a long time thought more of the fine creature than is generally realized.

Reflecting back on the incident during the final draft of his latest book, Darwin found it interesting to see that Augustus and Bartholomew both made the same number of true statements. (The number can be anything from 0 to 3.)

Who killed the tortoise?

Solution

Narrow down the true and false statements made by A and B.

If A2 is true, then B2 is true also making A2 is false, so consider A2 false.

If B2 is true then A and B have not made the same number of true statements, so B2 is false and not everything A says is false. A and B must have made at lease one true statement.

If A3 is true, then C2 is also true making B1 false and B3 false and A and B have not made the same number of true statements, so A3 is false and A1 is true (because A1 must have made at least one true statement). C1 is false.

If B3 is true, then C2 is false and B1 is true. But this is impossible as A and B now don’t have the same number of true statements. B3 is false making C3 true, B1 is true and C2 is false.

But since A1 and B1 are both true, A and B must be innocent.

Clements is guilty of herpicide and did indeed think more of the big animal.

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