Question

If in a for it to be complete it is necessary for switch A to be closed and either of switch B or C to be closed, then which can be true?

(a) Switch A should  in parallel with B and C is series to them

(b) Switch A should be in series with a parallel circuit of B and C

(c) All of the mentioned

(d) None of the mentioned

I had been asked this question at a job interview.

Question is from Logic Circuits topic in chapter The Foundation: Logics and Proofs of Discrete Mathematics

Answer 1

Correct choice is (b) Switch A should be in series with a parallel circuit of B and C

The best I can explain: Switch A is in series and since there is ‘or’ between B and C therefore they must be in parallel.