(iii) The complement of the Boolean expression (P·Q)′ + R′ is:
(a) (P+Q).R
(b) PQR
(c) (P’+Q’) .R’
(d) (P’+Q’).R

Solution

(b) PQR

Explanation :

=(P·Q)′ + R′
=((P·Q)′ + R′)'
=((P.Q)')'.(R')' [De-morgans Law]
=P.Q.R [Involution Law]