Johnson Cogs wants to set up a line to serve 60 customers per hour. The work elements and their precedence relationships are shown in the following table.
a. What is the theoretical minimum number of stations?
b. How many stations are required using the longest work element decision rule?
c. Suppose that a solution requiring five stations is obtained. What is its efficiency?
|
Work Element
|
Time (Sec)
|
Immediate Predecessor(s)
|
|
A
|
40
|
None
|
|
B
|
30
|
A
|
|
C
|
50
|
A
|
|
D
|
40
|
B
|
|
E
|
6
|
B
|
|
F
|
25
|
C
|
|
G
|
15
|
C
|
|
H
|
20
|
D, E
|
|
I
|
18
|
F, G
|
|
J
|
30
|
H, I
|
|
Total 274
|
|