A project schedule has the following characteristics:

Activity Time $($Weeks$)$ Activity Time $($Weeks$)$

$1-245-64$

$1-315-78$

$2-416-81$

$3-417-82$

$3-568-105$

$4-959-107$

$1)$ Compute earliest start time $($Es$)$ and latest finish time $($Lf$)$ for each event.

$2)$ Compute Total float and critical path.