=+ 2 a simple process has four stages:

a, B, C and D. the average amount of work needed to process items passing through these stages is as follows: stage a = 68 minutes, stage B = 55 minutes, stage C = 72 minutes and stage D = 60 minutes. a spot check on the workin-progress between each stage reveals the following: between stages a and B there are 82 items, between stages B and C there are 190 items, and between stages C and D there are 89 items.

(a) Using Little’s law (see Chapter 6 ) , calculate the throughput time of the process.