the demand for subassembly s is $130$ units in week $7.$ each unit of s requires $1$ unit of t and $1$ unit of u$.$ each unit of t requires $2$ units of V$,1$ unit of W$,$ and $2$ units of x$.$ finally, each unit of u requires $1$ unit 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$,3$ weeks to make w$,1$ week to make x$,2$ weeks to make y$,$ and $1$ week to make z