Using utilization to determine the bottleneck is not necessary, because the denominator in

the utilization ratio is the same for every work station, with one worker per machine at

each step in the process. So we identify the bottleneck by computing aggregate work

loads at each work station. The firm wants to satisfy as much of the product demand in a

week as it can. Each week consists of $2400$ minutes of available production time.

Multiplying the processing time at each station for a given product with the number of

units demanded per week yields the capacity load. These loads are summed across all

products going through that workstation and then compared with the existing capacity of

$2400$ minutes.