Final answer:
Ian's Laotian Bake Shop can achieve a value-added time of approximately 14 pastry units per hour with their current ovens.
Step-by-step explanation:
When analyzing the value-added time of the pastry ovens, Ian's Laotian Bake Shop considers the availability and productivity of the ovens. The bakery is open for 6 hours, and the oven is available for 90% of that time, resulting in 5.4 hours of availability. With a total time of 23 minutes required to make a pastry unit, the pastry oven can produce approximately 14 pastry units per hour. This value-added time calculation helps the bakery assess the efficiency and productivity of their current ovens.