help needed below, and please add the excel formulas.

thank you.

GF Interior Design provides home and office decorating assistance to its customers. In normal operation, an average of 3 customers arrive each hour. One design consultant is available to answer customer questions and make product recommendations. The consultant averages 10 minutes with each customer. Service goals dictate that an arriving customer should not wait for service more than an average of five minutes. Is this goal being met? If not, what action do Questions you recommend? If the consultant can reduce the average time spent per customer to eight minutes, what is the mean service rate? Will the service goal be met? waiting time= Questions