Problems $14\mathrm{.}5-14\mathrm{.}21$ relate to MRP Structure

$-14\mathrm{.}5$ 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$,$