Consider one aisle of a miniload AS/R system used by a book distributor for order picking.

The P/D station is located at the lower lefthand corner of a rack that is 360 long and 63 tall. The S/R machine travels at 450 fpm and 90 fpm in the horizontal and vertical directions, respectively. It takes 0.15 minute to pick up or deposit a tray. On the average, the picker picks eight books from each tray. Time and motion studies indicate that, including the necessary paperwork, on the average it takes the picker 15 seconds to pick one book. It has also been determined that the total time required to make the necessary picks from a tray is exponentially distributed.

a. Compute the expected dual-command cycle time for the above system.

b. Suppose the expected dual-command cycle time is equal to 2.30 minutes per cycle.

Compute the number of books picked per hour by the above picker.