5. Costs in the short run versus in the long run
Ike’s Bikes is a major manufacturer of bicycles. Currently,
the company produces bikes using only one factory. However, it is
considering expanding production to two or even three factories.
The following table shows the company’s short-run average total
cost (SRATC) each month for various levels of production if it uses
one, two, or three factories. (Note: Q equals the total quantity of
bikes produced by all factories.)
Number of Factories
Average Total Cost
(Dollars per bike)
Q = 100
Q = 200
Q = 300
Q = 400
Q = 500
Q = 600
1 360 200 160 240 400 720
2 540 300 160 160 300 540
3 720 400 240 160 200 360
Suppose Ike’s Bikes is currently producing 600 bikes per month
in its only factory. Its short-run average total cost isper
bike.
Suppose Ike’s Bikes is expecting to produce 600 bikes per
month for several years. In this case, in the long run, it would
choose to produce bikes using .
On the following graph, plot the three SRATC curves for Ike’s
Bikes from the previous table. Specifically, use the green points
(triangle symbol) to plot its SRATC curve if it operates one
factory ( SRATC1
SRATC
1
); use the purple points (diamond symbol) to plot its SRATC
curve if it operates two factories ( SRATC2
SRATC
2
); and use the orange points (square symbol) to plot its SRATC
curve if it operates three factories ( SRATC3
SRATC
3
). Finally, plot the long-run average total cost (LRATC) curve
for Ike’s Bikes using the blue points (circle symbol).
Note: Plot your points in the order in which you would like
them connected. Line segments will connect the points
automatically.
SRATC
1
SRATC
2
SRATC
3
LRATC
0
100
200
300
400
500
600
700
800
720
640
560
480
400
320
240
160
80
0
AVERAGE TOTAL COST (Dollars per bike)
QUANTITY (Bikes)
In the following table, indicate whether the long-run average
cost curve exhibits economies of scale, constant returns to scale,
or diseconomies of scale for each range of bike production.
Range
Economies of Scale
Constant Returns to Scale
Diseconomies of Scale
Fewer than 300 bikes per month
Between 300 and 400 bikes per month
More than 400 bikes per month