$(7)$ Canvas

$20.$ Consider the product structure tree shown below:

With a beginning inventory of five for all components on level one, ten for all components on level two, and zero for all components on level three and finished items, how many assembly F$\text{'}$s are needed to produce $60$ product X$\text{'}$s$?($Hint$.$ You don't need to develop an MRP table to determine this; instead you may find the attached table helpfut $-$ which is partially filled.$)$

$\backslash$table$[[$Level$,$Item,GR from?,GR$,$OH$,$NR$],[0,$X$,$MPS$,60,0,60],[1,$A$,2*$NR$($X$),120,,],[1,$B$,1*$NR$($X$),60,,],[1,$C$,3*$NR$($X$),180,,],[,,,,,],[,,,,,],[,,,,,],[,,,,,],[,,,,,],[,,,,,],[,,,,,]]$