Is there anyone telling the truth these days?

Logic Level 2

Abby, Bobby, Clyde, David, and Evangeline are causing trouble by confusing people with weird statements, and you have to break all their shenanigans. You make an ultimatum: if you solve a riddle of their creation, they have to stop causing trouble. The five agree to your conditions and start making statements:

  • Abby: I am telling the truth
  • Bobby: Clyde or Abby is lying but not both.
  • Clyde: I am telling the truth.
  • David: Bobby is telling the truth.
  • Evangeline: Clyde is telling the truth.

Given that there is only one answer, all people in the answer choices have made a statement, and statements must be true or false but not both, which person is telling the truth?

Hint: Look at the answer choices.

Abby David Clyde Bobby Eric

Anthony Ling by Anthony Ling , 24, USA

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

4 solutions

Zoe Codrington
Jun 3, 2019

Only one person can be telling the truth Therefore, if Clyde is telling the truth, so is Evangeline, so they are both lying. Simarly, if Bobby is telling the truth, David is too and they are both lying. Since both Bobby and Clyde are lying, Abby must also be lying. In fact, all the speakers are lying!

Using the hint, we check the answer choices. We have already established that Clyde, Abby, Bobby and David are all lying, therefore the only possible truth teller is Eric.

0 Helpful 0 Interesting 0 Brilliant 0 Confused
Xeeshan Alam
Jan 11, 2019

Odd question

0 Helpful 0 Interesting 0 Brilliant 0 Confused

Odd answer

Anthony Ling - 2 years, 5 months ago
Malcolm Rich
Jan 7, 2019

All scenarios lead to more than one of A,B,C,D telling the truth.

Eg if Abby is telling the truth then either Bobby or Clyde must be.

The only option is the person who says nothing ie Eric

0 Helpful 0 Interesting 0 Brilliant 0 Confused

If the person doesn't say anything, how can they be telling the truth? (I'm not criticizing anything, your answer is perfect).

Anthony Ling - 2 years, 5 months ago
Anthony Ling
Jan 4, 2019

Eric is not Evangeline

That being said, let's look at all possible combinations of "truths" for the first three characters.

  • Abby: True, Clyde: True, Bobby: False
  • Abby: True, Clyde: False, Bobby: True
  • Abby: False, Clyde: True, Bobby: True
  • Abby: False, Clyde: False, Bobby: False

All of them being "False" is the only one that doesn't violate "the one answer" rule yet, so this is the combination that must be part of the right answer.

David is dependent on whether Bobby is "True" or "False", so David is "False"

Eric is the only person that can be the correct answer, so he must be the truth teller.

2 Helpful 4 Interesting 2 Brilliant 6 Confused

I think the "given" statement that "statements must be true or false but not both" could be false.

It has been already discussed in many places that statements like "I am lying" are neither true or false.

Conversely, the statement "I am telling the truth" is both true and false! It's true because the speaker is telling the truth but it's also false because the speaker is telling a falsehood.

Tapani Lindgren - 2 years, 4 months ago

Log in to reply

Yes that's definitely true, but for the context of this problem, assume that the given statement is correct.

Anthony Ling - 2 years, 4 months ago

The statement can function as either true or false.

Zoe Codrington - 2 years ago

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...