Answer: (p ∨q∨r)∧s
Step-by-step explanation:
Our proposition is:
(p /\ q/\ r) v s
This means
(P and Q and R ) or S
The proposition is true if P, Q and R are true, or if S is true.
Then the dual of this is
(P or Q or R) and S
The dual of a porposition can be obtained by changing the ∧ for ∨, the ∨ for ∧, the Trues for Falses and the Falses for Trues.
Then, the dual can be writted as:
(p ∨q∨r)∧s
The proposition is true if S is true, and P or Q or R are true.