What is the minimum cost of crashing the following project t

What is the minimum cost of crashing the following project that James Walters manages at Athabasca University by 4 days? ash Time Nor rash Cost Immediate Predecessor(s) Activity Time (days (days) Cost 200 S600 S750 $1,200 5600 650 $1,500 $1,650 By how many days should each activity be crashed to reduce the project completion time by 4 days? Fill in the table below. (Enter your responses as whole numbers.) Each Activity Should be Reduced BY days) Activity The total cost of crashing the project by 4 days is S(Enter your response as a whole number.)

Solution

The precedence diagram as follows :

A

                        B

C

D

E

The parallel paths and their corresponding durations as follows :

A-D = 5 + 5 = 10 days

B = 7 days

C- E = 4 + 7 = 11 days

Since C-E has the longest duration , it forms the Critical Path. Duration of critical path is same as normal duration of the project. Therefore, normal duration of the project will be 11 days

To reduce project completion time by 4 days, the revised project duration will be 7 days.

Project duration of 7 days will be achieved by:

By Crashing C by 1 day

By Crashing E by 3 days

By Crashing A by 1 day

By Crashing D by 2 days

Activity

Each activity should be reduced by ( Days)

A

1

B

0

C

1

D

2

E

3

Total cost of crashing the project by 4 days, $

= Crashing cost of A + Crashing cost of C + Crashing cost of D + Crashing cost of E

= Sum of ( Crash cost – Normal cost ) of all above activities

= (1000 – 800)+ ( 650 – 600) + ( 1500 – 750 ) + ( 1650 – 1200 )

= 200 + 50 + 750 + 450

= $1450

THE TOTAL COST OF CRASHING THE PROJECT BY 4 DAYS = $1450

A	B	C
D	E