Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
National Exams — December 2015 — 04-BS-8 Digital Logic Circuits. Three-hour, closed-book exam (Casio or Sharp approved calculator only; one hand-written 8.5"×11" aid sheet permitted). Format: five questions offered, each worth 25 marks (100 total); any four constitute a complete paper and only the first four appearing in the answer book are marked. All five are solved below for completeness.
Reference texts: Mano & Ciletti, Digital Design (6th ed., Pearson) — Boolean minimization, PAL/PLA/FPGA architectures, flip-flop conversion, sequential design, arithmetic circuits; Floyd, Digital Fundamentals (11th ed., Pearson) — decoders, number systems, flip-flop characteristic tables, counters.