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Apples, Bananas, and Oranges Puzzle (Posted on 2022-06-25) Difficulty: 2 of 5
Quentin, Raynor, and Seth work at a grocery store that sells apples, bananas, and oranges.

It is known that precisely two of the men are knights, who always speak truthfully, and the remaining man is a liar, who always tells lies.

They make the following statements:
  • Quentin: Seven apples and five bananas cost precisely the same as six oranges.
  • Raynor: Four apples and nine oranges cost precisely the same as five bananas.
  • Seth: Six oranges and three bananas cost precisely the same as four apples.
Determine the type of each of the three men from the abovementioned clues.

See The Solution Submitted by K Sengupta    
Rating: 5.0000 (1 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
Solution Solution | Comment 2 of 3 |
Let a,b,c be the cost of apples, bananas, and oranges ("c" because oranges have Vitamin C).

Q said:  7a + 5b - 6c = 0
R said:  4a - 5b + 9c = 0
S said:  4a - 3b - 6c = 0

eqns 1&2: 11a + 3c = 0
eqns 1&3: 3a + 8b = 0
eqns 2&3: -2b + 15c = 0

The only way you don't conclude that some item has a negative (or zero) cost is with the last option, so Quentin is the liar

Edited on June 25, 2022, 12:51 pm
  Posted by Larry on 2022-06-25 12:50:08

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