Final answer:
A perpetual inventory system is a system that keeps inventory continuously updated in real-time. It is used by both merchandising companies and service companies to monitor and manage their inventory levels.
Step-by-step explanation:
A perpetual inventory system is a system that keeps inventory continuously updated.
Unlike a periodic inventory system, which updates inventory at the end of the month based on a physical count, a perpetual inventory system maintains control over inventory in real-time.
It is used by both merchandising companies and service companies to monitor and manage their inventory levels.