Final answer:
Without knowing the number of mattresses bought by the 19 small furniture stores, it is impossible to accurately determine the total monthly mattress sales for Sleepeze Company.
Step-by-step explanation:
The question deals with activity-based customer costing at Sleepeze Company, which is a concept relevant to managerial accounting in the business field. The Sleepeze Company produces mattresses for 20 retail outlets. To calculate the total number of mattresses purchased by all the retail outlets per month, we should add the number of mattresses purchased by the retail chain to the quantity purchased by the other 19 small, separately owned furniture stores. The question supplies the information that the retail chain buys 60 mattresses per month. If each of the other 19 stores also buys mattresses, we need to know the number they purchase to complete the calculation. Without this additional information, we cannot determine the total number of mattresses sold per month.