If the restaurant runs a sale and the customer arrival rate increases by 20%, how would this change the total time expected to serve a customer? How would this change the average number of cars in the drivethru line

Explanation: when the total number of customers * increases*, in order to serve the increased number of customers, it needs to be done * faster * in order not to keep other customers waiting for too long. And also this increased customer patronage would increase as well, the number of cars driving through the drive way