TAHUN AKADEMIK 2004/2005
PROGRAM : BE Hons . Mechanical Engineering
MATAPELAJARAN : Industrial Engineering
KOD MATAPELAJARAN : MEFB443
MASA : Three (3) hours
Instructions to candidates:
1. Answer all questions
2. Questions marks are individually assigned
3. There are total six questions in this paper
4. Total marks are 100
DO NOT OPEN THIS QUESTION PAPER UNTIL YOU ARE INSTRUCTED TO DO SO
THIS QUESTION PAPER CONSISTS OF SEVEN PRINTED PAGES INCLUDING
Q1. Refer below to bill of material for product A. If there are 2
units of B, 1 units of F, and 3 units of G in inventory, how many
units of G, E, and D must be purchased to produce 5 units of
LT = 1
LT = 2 LT = 3
D(1) E(2) F(1) D(1)
LT = 3 LT = 6 LT = 1 LT = 3
LT = 3
Q2. A firm uses a continuous review system and operates 52
weeks per year. One of the items handled has the following
Demand (D) = 20,000 units/year
Ordering cost (8) = $40/order
Holding cost (H) = $2/unit/year
Lead time (L) = 2 weeks
Cycle-service level = 95 percent
Demand is normally distributed, with a standard deviation of
weekly demand of 100 units.
Current on-hand inventory is 1,040 units, with no scheduled
receipts and no backorders.
a. Calculate the item's EOQ. What is the average time, in
weeks, between orders?
b. Find the safety stock and reorder point that provide a 95
percent cycle-service level.
c. For these policies, what are the annual costs of (i) holding
the cycle inventory and (ii) placing orders?
d. A withdrawal of 15 units just occurred. Is it time to
reorder? If so, how much should be ordered?
Q3. The Trim-Look Company makes several lines of skirts, dresses,
and sport coats. Recently, a consultant suggested that the
company reevaluate its South Islander line and allocate its
resources to products that would maximize contribution to profits
and to overhead. Each product requires the same polyester fabric
and must pass through the cutting and sewing departments. The
following data were collected for the study:
The cutting department has 100 hours of capacity, sewing has
180 hours of capacity, and 60 yards of material are available.
Each skirt contributes $5 to profits and overhead; each dress,
$17; and each sport coat, $30
a. Specify the objective function and constraints for this
From the computer solution given below answer the followings:
b. How much would you be willing to pay for an extra
hour of cutting time? For an extra hour of sewing time? For an
extra yard of material? Explain your.
c. Determine the range of right-hand-side values over which
the shadow price would be valid for the cut- ting constraint
and for the material constraint.
Variable Variable Original Coefficient
Label Value Coefficient Sensitivity
X1 0.0000 5.0000 2.50
X2 20.0000 17.0000 0.00
X3 10.0000 30.0000 0.00
Constraint Original Slack or Shadow
Label RHV Surplus Price
cutting 100 0 4.7500
sew ing 180 40 0
material 60 0 2.7500
Objective Function Value: 640.00
Sensitivity Analysis and Ranges
Objective Function Coefficients
Variable Low er Original Upper
Label Limit Coefficient Limit
X1 No Limit 5 7.5
X2 7.5 17 22.5
X3 22.66666667 30 68
Constraint Low er Original Upper
Label Limit Value Limit
cutting 60 100 132
sew ing 140 180 No Limit
material 33.33333333 60 100
Q4. Dixie Bank in Dothan, Alabama, recently installed a new
automatic teller machine to perform the standard banking services
and handle loan applications and investment transactions. The new
machine is a bit complicated to use, so management is interested
in tracking its past use and projecting its future use. Additional
machines may be needed if projected use is high enough.
At the end of April, the average monthly use was 600 customers and
the trend was +60 customers per month. The actual use figures for
May, June, and July are 680, 710, and 790 respectively. Use trend-
adjusted exponential smoothing with a = 0.3 and = 0.2 to
forecast usage for June, July, and August.
Q5. Consider the following project information
a. Draw the network diagram for this project.
b. Specify the critical path.
c. Calculate the total slack for activities A and D.
d. What happens to the slack for D if A takes five
Q6. Multiple choice and T/F
i) An MRP system provides which of the following advantages?
a. Automatic update of the dependent demand and
replenishment schedules of components when parent
b. Statistical forecast of component demand
c. Smoothing of lumpy demand
d. None of the above
ii) The key inputs to an MRP include:
a. engineering drawing of the product.
b. process chart.
c. inventory record database.
d. both a and b.
iii) If gross requirements are 100, planned receipts are 120, and
inventory on hand from the previous period is 50, then the
projected on-hand inventory balance:
a. is 270.
b. is 170.
c. is 70.
d. cannot be determined from the data given.
iv) The portion of total inventory that varies directly with lot
size is called safety inventory. (T/F)
v) The average cycle inventory is the average of two extremes, the
maximum order size and minimum order size (zero). (T/F)
vi)During periods of uncertain demand, the reorder point (R)
equals demand during lead time. (T/F)
vii)Safety stock size is a trade-off between customer service
(availability) and inventory holding costs. (T/F)
viii) If lead time increases but average demand for the item per
period does not, the pipeline inventory will not increase. (T/F)
ix) A sample statistic that falls between the UCL and the LCL, but
not on the nominal value line when plotted on a control chart,
indicates that the process is exhibiting assignable causes of
x) The analysis tool for a quality problem that involves selecting
the problem, identifying the major categories of potential causes,
and associating likely specific causes is:
a. Pareto charts.
b. fishbone diagrams.
c. scatter diagrams.