$*14\mathrm{.}5$ The demand for subassembly $S$ is $100$ units in week $7.$ Each unit of $S$

requires $1$ unit of $T$ and $2$ units of $U.$ Each unit of $T$ requires $1$ unit of $V,2$ units of

$W,$ and $1$ unit of $x.$ Finally, each unit of $U$ requires $2$ units of $Y$ and $3$ units of $Z.$

One firm manufactures all items. It takes $2$ weeks to make $S,1$ week to make T$,2$

weeks to make U$,2$ weeks to make $V,3$ weeks to make $W,1$ week to make $x,2$

weeks to make $Y,$ and $1$ week to make $Z.$

a$.$ Construct a product structure. Identify all levels, parents, and

components.

b$.$ Prepare a time$-$phased product structure.