A actual average time is 79 seconds b normal time is

a. Actual average time is 79 seconds. b. Normal time is 79 * 1.20 = 94.8 seconds.
c. Standard time is 94.8 / (1-.14) = 110.23 seconds. d. The revised standard time is
94.8 / (1-.20) = 118.5 seconds. (Time studies, difficult) {AACSB: Analytic Skills}
62. A task involves positioning two metal parts with a rubber gasket sandwiched between them,
inserting two bolts into predrilled holes, threading a nut onto each bolt, and tightening each bolt
with a pneumatic wrench. In a preliminary study, the manager observed one of his workers perform
this task five times. The observations were made in an air-conditioned, well-lighted training
facility, at ground level, with all tools and equipment clean and readily available.
Observation: 1 2 3 4 5
Task time (seconds): 50 54 60 145 56
a. What is the average observed time for this task?
b. What is the normal time for this task if the employee worked at a 10% slower pace than is
typical for adequately trained workers?
c. What is standard time for this task if allowances are 8% constant and 6% variable?
Note that the fourth time must be discarded as an unusual event. a. Actual observed time is
220 / 4 = 55 seconds. b. Normal time is 55 * 0.90 = 49.5 seconds. c. Standard time is 49.5 /
(1-.14) = 57.6 seconds. (Time studies, difficult) {AACSB: Analytic Skills}

63. The data in the following table represent time-study observations on a new operation with three
work elements. On the basis of these observations, find the standard time for the process. Assume a
15% allowance factor.
Observations (times in seconds)
Element Performance Rating 1 2 3 4
1 120% 90.3 91.5 92.4 90.2
2 100% 30.5 32.3 29.6 31.1
3 105% 130.5 128.9 132 130.5
Answer:
Observations (times in seconds)
Element Rating 1 2 3 4 Average Normal
Time
1 120% 90.3 91.5 92.4 90.2 91.10 109.32
2
100% 30.5 32.3 29.6 31.1
30.88 30.88
3 105% 130.5 128.9 132 130.5 130.48 137.00
Normal time for process = 109.32 + 30.88 + 137.00 = 277.20 seconds
seconds 326.12 =
15 . 1
20 . 277
fraction Allowance - 1
time Normal
job for time Standard

 
(Time studies, moderate) {AACSB: Analytic Skills}

64. An operation in a television factory has an average observed time of 6 minutes. The performance
rating of the worker timed was estimated at 90%. Practice in this department is to allow 8% for the
constant allowances. Currently, there is no variable allowance.
a. Find the normal time for the operation.
b. Compute the standard time for the operation.
c. Recompute the standard time if a variable allowance of 8% is factored in.
a. Normal time = 6 minutes * .90 = 5.4 minutes
b.
minutes 5.87 =
08 . 0 1
4 . 5
factor Allowance - 1
time Normal
time Standard

 
c.
minutes 6.43 =
16 . 0 1
4 . 5
factor Allowance - 1
time Normal
time standard New

 
(Time studies, moderate) {AACSB: Analytic Skills}
65. An initial analysis of a laboratory activity resulted in the first table below. After this analysis, the
managers determined that their element descriptions were not as accurate as they should have been
—they had left out an element, underestimated a distance, and understated the need for accuracy.
They revised the table of element data, which appears in the second table.
Original Activity: Pouring tube specimen
Element description Element code TMU
Get tube from rack AA2 35
Get stopper, place on counter AA2 35
Get centrifuge, place at sample tube AD2 45
Pour (3 sec.) PT 83
Place tubes in rack (simo) PC2 40
TOTAL TMU
Revised Activity: Pouring tube specimen
Element description Element code TMU