Crashing Questions

Question 1 The information contained below to compress one time unit per move using the least cost method. Reduce the schedule until you reach the crash point of the network. For each move identify what activity(s) was crashed, the adjusted total cost, and explain your choice if you have to choose between activities that cost the same. If the indirect cost for each duration are $1,500 for 17 weeks, $1,450 for 16 weeks, $1,400 for 15 weeks, $1,350 for 14 weeks, $1,300 for 13 weeks, $1,250 for 12 weeks, $1,200 for 11 weeks, and $1,150 for 10 weeks, what is the optimum cost-time schedule for the project? What is the cost?

ID

Predecessor

A B C D E F G H I

None A A B,C C B F D,E G,H

DIRECT COST NORMAL CRASH Time Cost Time Cost 3 4 3 4 2 3 2 4 2

150 200 250 200 250 200 250 420 400

3 2 2 3 2 1 1 2 1

150 400 310 240 250 260 270 420 400

Question 2 You are given the following data about the project tasks, network, and crash times/costs. Calculate the cost of the project at all-time durations until you can no longer crash the project any further.

ID A B C D E F G

Predecessor None A A B C E D,F

DIRECT COST NORMAL CRASH Time Cost Time Cost 5 500 4 600 10 1200 6 2000 13 3600 11 4800 13 300 11 600 10 1000 4 1400 5 2400 8 5400 5 700 5 700

Question 3 Three recent university graduates have formed a partnership and have opened an advertising firm. Their first project consists of the following activities: ID A B C D E F G H I

Predecessor None None A None C D F B H

Optimistic 5 8 6 9 5 5 2 4 2

Duration in days Most Likely 6 8 8 12 6 6 3 4 7

Pessimistic 7 11 11 15 9 7 7 5 8

a. Draw the precedence network diagram. b. What is the probability that the project can be completed in 24 days or less? c. In 21 days or less? Question 4 For the project data below, determine (a) the normal project completion time, (b) how much extra it will cost to finish the project in 13 days, and (c) the minimum completion time with associated extra cost.

Act.

I.P.

Norm Time

Crash Time

A

Cost / Day

--

9

5

$1500

B

--

5

3

$1200

C

B

6

3

$2500

D

B

9

6

$1800

E

A,C

5

4

$1600

a) Normal completion time?

b) Cost to crash to 13 days?

c) Minimum completion time and cost?

Question 5 For the information below, first determine how long the project will take and what the project will cost under normal conditions. Then, determine how much each additional day crashed will cost, down to the minimum completion time. Finally, fill in the table below on the right with the total cost to complete the project depending on how many days it will take to complete. Days

Cost

15

14

13

12

11

10

9

8

7