BOBO Van is a start-up company which develops an app to receive orders from customers and provide delivery service. It owns one single vehicle. Two workers form a crew. The whole crew, which includes both workers working as a team, is needed to complete the delivery service. On average, an order arrives every 20 minutes while it takes 15 minutes on average to complete the order. If an order arrives while the crew is working on another order, the arriving order needs to join the waiting line for service. Assume the app provide adequate quota to accommodate essentially any number of orders waiting in the line.

The management finds that they have sufficient resources to purchase another identical vehicle to provide delivery service at the same time. They plan to add one more crew of two workers. The salary of each worker is $100 per hour and the cost of a waiting order is $500 per hour. If management decides to add the second crew:

Compared with a single crew operation, how much will be saved if two crews are used?

Group of answer choices

$416.65

$33.35

$863.65

$450

$461.35