City Guilds Model Questions Vol1 2020 Engineering Question 42

A workshop of total floor area \(250\) m² is divided into two zones. Zone A (\(150\) m²) contains class B fire‑hazard equipment, while zone B (\(100\) m²) contains class C equipment. Two types of portable fire extinguishers are available:\n\n- Type X: 6 kg capacity, costs \(\text{₦}12{,}000\), effective radius \(30\) m.\n- Type Y: 3 kg capacity, costs \(\text{₦}7{,}000\), effective radius \(20\) m.\n\nRegulations require that (i) the total extinguishing capacity in zone A be at least \(12\) kg and in zone B at least \(6\) kg, and (ii) every point in a zone be within the effective radius of at least one extinguisher placed in that zone. Determine the least‑cost combination of extinguishers that satisfies the regulations and give the total cost.