$4\mathrm{.}11$ The developement of an electronic widget is expected to follow the following steps.

$\backslash$table$[[$Activity$,$Description,Time est., weeks,Preceded by$],[$A$,$Define customer needs,$4,],[$B$,$Evaluate competitor's Product,$3,],[$C$,$Define the market,$3,],[$D$,$Prepare Product specs,$2,],[$E$,$Produce sales forecast,$2,$B$],[$F$,$Survey competitor's marketing methods,$1,$B$],[$G$,$Evaluate product vs$.$ customer needs,$3,$B$],[$H$,$Design and test the product,$5,$A$,$D$],[$I$,$Plan marketing activity,$4,$A$,$B$,$D$],[$J$,$Gather information on competitor's pricing,$2,$C$,$F$],[$K$,$Conduct advertising campaign,$2,$B$,$E$,$G$],[$L$,$Send sales literature to distributors,$4,$I$],[$M$,$Establish product pricing,E$,$G$,]]$

Determine the arrow network diagram and determine the critical path by using the CPM technique.