Answer:
Step-by-step explanation:12 customers per hour..
4minutes per customer..
Time customers must wait= 12customers ×4minutes =48 minutes.. The clerk use 48minutes to attend to 12customers in one hour leaving him with 12spare minutes.
(B)since the clerk has 12 minute to spare it means each customer have a minute to wait before getting attention..
(C)number of customers waiting =12/2=6customers...