Question

ZAKI LLP is a networking entity.

Required

Using the data provided below

1. Draw an A-O-A diagram based on normal times and identify the critical path, calculate the normal cost for the project.
2. Determine the minimum project completion time with the least cost and calculate the percentage increase in costs.
3. Use the network diagram in (a) above to construct a simple Gantt chart.

Note: Time is in Weeks and Cost in USD.

Activity	Normal time	Crash time	Normal cost	Crash cost
1-2	10	7	1,000	1,600
1-3	15	10	2,000	3,000
2-4	8	6	1,800	2,600
2-5	20	16	4,500	5,300
3-6	30	20	7,200	9.600
4-5	14	12	5,000	6,000
5-6	12	9	3,300	4,500

Answer 1

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b)

Activity	Normal Time	Normal Cost	Crash time	Crash cost	Cost slope
1--2	10	1,000	7	1,600	200
1--3	15	2,000	10	3,000	200
2--4	8	1,800	6	2,600	400
2--5	20	4,500	16	5,300	200
3--6	30	7,200	20	9,600	240
4--5	14	5,000	12	6,000	500
5--6	12	3,300	9	4,500	400
		24,800

C)

Step 1: The critical activity 1-3 has least cost slope of 200 USD. So we can crash it by one week. Then duration will be 44 weeks at as cost of 24800+200= 25000 USD

Step:2 The critical activity of 1-2 & 1-3 has least cost slope of 200USD. So we can crash each activity by 2 weeks.

Then duration will be 42 Weeks at a cost of 25000+400+400= 25900 USD

Therefore the minimum project completion time with the least cost is 42 weeks @ 25900 USD