Did you notice the OneLiver Quiz in support(gary)’s moment today?

Do you know the answer?

Unlike the quizzes in the past which you only need to understand the rules well and read our Tips&News, you may need to take some time to deduce the correct answer for this one.

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How can we solve it?

First, read carefully.

Two of them are lying while the other two are telling the truth.

So, A, B, C, and D each gives a statement, and we know that two of the statements are true, while the other two are false.

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Now, read again what the 4 girls are saying.

The key is C’s statement.

C says A is lying. That means either C is telling the truth and A is lying, or A is telling the truth and C is lying.

C’s statement contradicts A’s

C also says she had video call with John, but B says C didn’t have any video call.

C’s statement also contradicts B’s

D says John “only” had video call with B and herself. That implies that C didn’t have video call with John.

C’s statement also contradicts D’s

Therefore, if C is telling the truth, then A, B, and D must be lying. However, we know that only two persons are lying and two are telling the truth, that means A, B, and D cannot be all lying.

So, C is not telling the truth. C’s statement is false.

A:

B:

C: False

D:

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Now we know that C is lying. Read again C’s statement, then you can tell that:

A is telling the truth. (Because C says A is lying)

Hence,

A: True

B:

C: False

D:

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Since only two persons are lying and two are telling the truth, now we know that there can only be 2 possibilities:

B: True & D: False

or

B: False & D: True

Again, D says John “only” had video call with B and herself. That implies that A didn’t have video call with John.

But we already know that A is telling the truth and she had video call with John!

That means D must be lying.

A: True

B: True

C: False

D: False

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Now, who definitely had video call with John?

The answer is

 

 

 

A