ISRO | ISRO CS 2017 | Question 6

The proposition (P⇒Q)⋀(Q⇒P) is a

(A) tautology
(B) contradiction
(C) contingency
(D) absurdity

Answer: (C)
Explanation: (P⇒Q)⋀(Q⇒P) = (¬P+Q)(¬Q+P) = (¬P¬Q + ¬PP + ¬QQ + PQ) = (¬P¬Q + PQ)
Therefore it is a contingency.
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