Z Ltd sells Product A for which there is variable demand. On a daily basis, demand for this product usually ranges between 40 and 20 items. The average demand per day is 30. The owner of the store works a standard week; i.e. 8 hours per day, 5 days per week. Each order contains only one item of product , and each item of Product A takes 13 minutes to install. Z Ltd plans to add a second product, Product B, for which the average daily demand is expected to be 5 items. Each of these items takes 12 minutes to install. Required: Assuming the owner is the only worker and Product B is added, the average waiting time in minutes is ____________ ?

96.5 minutes

390.0 minutes

60.0 minutes

720.0 minutes