Activity 7 is directly preceded by two activities,activity 5 and activity 6.Activity 5 has an expected time of 5 and ES time of 6.Activity 6 has an expected time of 7 and an ES time of 7.Activity 7 has an expected time of 10.The ES for activity 7 is
A)10
B)11
C)14
D)21
E)24

Question

Quizplus · Accepted Answer

Activity 7 can start only after activity 6 is completed, which has an ES time of 7. Therefore the earliest start time for activity 7 is 7. 
Activity 7 has an expected time of 10, so the earliest finish time for activity 7 is 7+10 = 17. 
Therefore, ES for activity 7 is 17-10 = 7. 
Hence, the correct answer is option C.

Activity 7 Is Directly Preceded by Two Activities,activity 5 and Activity