Question

Activity 7-8 is directly preceded by two activities—activity 5-7 and activity 6-7. Activity 5-7 has an expected time of five and an ES time of six. Activity 6-7 has an expected time of seven and an ES time of seven. Activity 7-8 has an expected time of 10. The ES for activity 7-8 is:

A. 11
B. 14
C. 21
D. 24
E. 25

Answer 1

B. 14

Step-by-step explanation:

ES = early start

ES = finished point of the predecessor activity

Considering we have two activities which are:

5-7 which is expected to start at 6 and finish in 5 thus It will end at 11

6-7 which is expected to start at 7 and has a duration of 7 thus, ending at 14

The 7-8 activity will start as soon as the precedecessor end. These activities are finished at point 14 thus, that is the earliest activity 7-8 can start.