Question

Coleman Rich Control​ Devices, Inc., produces​ custom-built relay devices for auto makers. The most recent project undertaken by Rich requires 14 different activities.​ Rich's managers would like to determine the total project completion time​ (in days) and those activities that lie along the critical path. The appropriate data are shown in the following table:          

	Time​ (days)						Immediate		Time​ (days)						Immediate
Activity	a		m		b		​Predecessor(s)	Activity	a		m		b		​Predecessor(s)
A	3		7		8		—	H	3		3		6		​E, F
B	1		3		4		—	I	3		5		9		​G, H
C	6		6		6		A	J	2		6		9		I
D	5		8		12		A	K	7		10		12		I
E	2		10		19		​B, C	L	3		5		6		J
F	2		3		8		D	M	1		3		5		K
G	3		5		9		D	N	6		8		12		​L, M

​a) The expected completion time of the project​ = _______days ​(round your response to two decimal​ places).

The activities that represent the project's critical path are _____________________________

b) If the time to complete the activities on the critical path is normally distributed, then the probability that the critical path will be finished in 53 days or less = _______

c) Number of days that would result in 99% probability of completion = ______ days.

Answer 1

Below is the screenshot of the formula applied -

Below is the screenshot of the result -

a) The expected completion time of the project​ = 52.67 days ​(round your response to two decimal​ places).

The activities that represent the project's critical path are A-C-E-H-I-K-M-N

b) If the time to complete the activities on the critical path is normally distributed, then the probability that the critical path will be finished in 53 days or less = 0.5382

c) Number of days that would result in 99% probability of completion = 60.76 days.