Four persons, A, B, C, and D, said as follows :
A said "B is a liar."
B said "C is a liar."
C said "D is a liar."
D said "A is a liar."
How many liars are there among these four persons ?
Answer
Two persons
Solution
In case A is a liar, C is also a liar and B and D are the honest.
In case A is the honest, B and D are liars and C is the honest.
In any cases, liars are two.
