As implied by the network, tasks A and B can be done independently of tasks C and D$.$ But B

cannot start until A is done, and D cannot start until C is done. $($This is called a $$finish$-$to$-$start$$

task dependency, by far the most common type. $$Start$-$to$-$start,$$finish$-$to$-$finish,$$ etc. also exist

and can be specified in Microsoft Project$).$

Time required to do each task is uncertain. Very often, the triangular distribution is used to

estimate the duration of a task. The minimum is $$everything went right $[$heh heh$],$ the mode is

the most likely duration, and the maximum is $$lots of things went wrong.$$ Assume the

following: