Final answer:
Mary's standard time for the memory-chip tests, considering her performance rating and the firm's allowances, is approximately 12.83 seconds.
Step-by-step explanation:
To calculate Mary's standard time for the memory-chip tests, we need to consider her performance rating and the firm's allowances. The average observed time for the tests is 15 seconds, but with a performance rating of 95%, Mary's effective time will be reduced. To find the standard time, we multiply the observed time by the performance rating and the personal fatigue and delay allowance. The formula is:
Standard Time = Observed Time x Performance Rating x Allowance
Given that the observed time is 15 seconds and the performance rating is 95% (0.95), and the personal fatigue and delay allowance is 10% (0.9), we can calculate Mary's standard time:
Standard Time = 15 x 0.95 x 0.9 = 12.83 seconds
Therefore, Mary's standard time for the memory-chip tests is approximately 12.83 seconds.