If a skilled wrapped does 4000 egg rolls in an 8-hour day, then he does 4000 / 8 = 500 egg rolls per hour. It means that he can make 500 / 60 = 8,(33) egg rolls per minute. So Bettie's claim is not reasonable.
It would be reasonable if the wrapper would make 1 * 60 = 60 egg rolls per hour and 60 * 8 = 480 egg rolls in one shift. So she's far away from truth :)