Question

A worker-machine operation was found to involve 4.6 minutes of machine time per cycle in the course of 40 cycles of stopwatch study. The worker’s time averaged 3.1 minutes per cycle, and the worker was given a rating of 121 percent (machine rating is 100 percent). Midway through the study, the worker took a 10-minute rest break. Assuming an allowance percentage of 13 percent of work time which is applied only to the worker element (not the machine element), determine the standard time for this job.

(Do not round intermediate calculations. Round your final answer to 2 decimal places.)

Answer 1

No. of cycles = 40 cycles

Average Machine time = 4.6 minutes

Total Machine time = 4.6 * 40 = 184 minutes

Average worker time = 3.1 minutes

Total worker time = 3.1 * 40 = 124 minutes

Break taken = 10 minutes

Rating of machine = 100%

Rating of worker = 121%

Allowance = 13%

Allowance factor per day = 1 / (1 - 0.13) = 1.149

Hence, total standard time = T(otal machine time * Rating of machine) + (Total worker time * rating * Allowance factor per day for worker) = (184 * 100%) + (124 * 121% * 1.149 ) = 184 + 172.4  = 356.4 minutes

Standard time for job = Total standard time / No. of cycles = 356.4 / 40 = 8.91 minutes

The standard time for this job = 8.91 minutes

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