Consider the network described in the table below.

Activity Immediate Predecessor$($s$)$ Pessimistic Probable Optimistic

J $--15108$

K $--987$

L J $1065$

M J $333$

N K$,$ M $951$

O K$,$ M $1074$

P L$,$ N $1083$

Consider the network described in the table below.

Activity Immediate Predecessor$($s$)$ Pessimistic Probable Optimistic

J $--15108$

K $--987$

L J $1065$

M J $333$

N K$,$ M $951$

O K$,$ M $1074$

P L$,$ N $1083$

Draw the network diagram and answer the following questions.

$($a$)$ Calculate the expected duration of each activity.