Zeal Test Series 2019: Mathematical Logic - Propositional Logic

Question

Isn’t the 3) statement is wrong it should be [(p->r)^(q->r)]->[(p∨q)->r]

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Comments

its answer given all 3 i am getting 1 and 2

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$3^{rd}$ is Tautology.

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yeah, all are tautology, for case 3, just fill truth table for the entries where RHS will be will be false.

Answer 1

All the three are tautologies. 

Option 1 can be resolved.

Option B and C can be quickly verified by substituting the values of P,Q,R,S

Hence option d is correct.