A call centre currently has 30 service agents to answer customers' phone calls. Suppose that the service time (i.e., phone call duration) distribution is identical for all customers (regardless of which agent answers the phone). The current utilization of each agent is equal to 90%. The manager of the call centre would like to reduce the agent utilization rate to 75% or less (so that it is more likely for a customer not having to wait when s/he calls in). At least how many agents in total is required to achieve this goal? (Suppose that both arrival rate and average phone call duration stay the same.) 29 32 34 36