Write a linear model for minimizing the overall number of years it takes to complete all the actions.
There are nine actions, A1,A2,A3,A4,A5,A6,A7,A8,A9.
Number of years it takes to complete each action { a1=6, a2=8 , a3=16 , a4=14 , a5=4 , a6=12, a7=2 ,a8 = 10, a9= 6}.
A1, A2 and A8 have no predecessors.
A3's predecessor is A2.
A4's predecessor is A1 and A2.
A5's predecessor is A3.
A6's predecessor is A3.
A7's predecessor is A4.
A9's predecessor is A4.
Multiple actions can be worked on at the same time.