A worker-machine operation was found to involve 3.6 minutes of machine time per cycle in the course of 40 cycles of stopwatch study. The worker’s time averaged 2.5 minutes per cycle, and the worker was given a rating of 120 percent (machine rating is 100 percent). Midway through the study, the worker took a 10-minute rest break. Assuming an allowance factor of 12 percent of work time, determine the standard time for this job.
The Correct Answer and Explanation is :
To determine the standard time for the worker-machine operation, we need to account for the worker’s performance rating and the allowance factor. Here’s how to calculate it:
1. Calculate the Basic Time:
The basic time is the observed time adjusted for the worker’s performance rating. The worker’s average time per cycle is 2.5 minutes, and the performance rating is 120%. To adjust for the rating, we multiply the observed time by the rating factor (120% or 1.2):
2. Calculate the Total Time per Cycle:
The total time per cycle includes both the worker’s time and the machine’s time. The machine time per cycle is 3.6 minutes. Therefore, the total time per cycle is:
3. Apply the Allowance Factor:
The allowance factor accounts for rest periods, delays, and other factors that may affect the worker’s performance. An allowance factor of 12% is given. To apply this, we multiply the total time per cycle by 1 plus the allowance factor (1 + 0.12 = 1.12):
Therefore, the standard time for this job is approximately 7.39 minutes per cycle.
Explanation:
The standard time represents the time required to perform a task under normal working conditions, considering both the worker’s performance and allowances for rest and delays. By adjusting the observed time for the worker’s performance rating and adding the machine time, we obtain the total time per cycle. Applying the allowance factor ensures that the standard time accounts for necessary rest and potential delays, providing a realistic estimate of the time needed to complete the task.