I'm struggling with part e. apparently 40 is the incorrect answer so I'm not sure how to solve it.

The Action Toy Company has decided to manufacture a new train set, the production of which is broken into six steps. The demand for the train is 4,500 units per 40 -hour workweek: This exercise only contains parts b,c,d,, and f. b) Given the demand, the cycle time for the production of the new train set = one decimal place). seconds (round your response to c) The theoretical minimum number of workstations =4 (round your response up to the next whole number). d) Using the longest operation time rule, the assignment of tasks to workstations should be: (Hint: Number workstations sequentially in terms of precedence relationships and combine any applicable tasks.) Were you able to assign all the tasks to the theoretical minimum number of workstations? e) The total idle time per cycle for the process = seconds (enter your response as a whole number)