Could you explain each step and formulations please?

In a plant, forklifts are used to deliver the materials between the departments. The following From-to churt displays the daily mumber of loads carried (above the slash) and the distances in meters (below the slash) travelled between the five departments of the plant. A day consists of 8 hours DI D2 D3 D4 DS From Di 0 12/45 11/30 15/54 D2 0 12/35 D3 . - 0 - 11/42 D4 - 0 27/65 DS . 0 Loading and unloading times per delivery are 2.25 and 2.00 minutes, respectively. The loaded vehicle velocity is aswned to be 0.75 m/se, and the empty vehicle velocity is taken 0.90 ma se Availability is assumed as 92%, and workers are 85% efficient. The anticipated traffic factor is 90%. Draw the network diagram of the system. How many forklifts will be required to operate this system a. If the forklifts never travel unloaded (empty? b. If the unloaded distance that the forklifts travel is equal to their loaded distance