Given the following sensitivity report from Excel SOLVER for a maximization LP problem:

Variable Cells

$\backslash$table$[[$Cell$,$Name,$\backslash$table$[[$Final$],[$Value$]],\backslash$table$[[$Reduced$],[$Cost$]],\backslash$table$[[$Objective$],[$Coefficient$]],\backslash$table$[[$Allowable$],[$Increase$]],\backslash$table$[[$Allowable$],[$Decrease$]]],[C$$$4,x1,\sqrt[\phantom{2}]{06},0,3,1,1\mathrm{.}5],[$$D$$4,$X$2,7\mathrm{.}2,0,3,3,0\mathrm{.}75]]$

Constraints

$\backslash$table$[[$Cell$,$Name,$\backslash$table$[[$Final$],[$Value$]],\backslash$table$[[$Shadow$],[$Price$]],\backslash$table$[[$Constraint$],[$R$.$H$.$ Side$]],\backslash$table$[[$Allowable$],[$Increase$]],\backslash$table$[[$Allowable$],[$Decrease$]]],[$$E$$8,,15,0\mathrm{.}6,15,1,9],[$$E$$9,,24,0\mathrm{.}6,24,36,1\mathrm{.}5]]$

$(1)$ What is the current optimal solution, that is$,x1=?x2=?$ What is the current optimal objective value, that is$,z=s?$

$(2)$ What is the new optimal objective value $(z)$ if the right$-$hand$-$side coefficient of the first constraint $($b$1)$ changes to $13?$

$(3)$ What is the new optimal objective value $(z)$ if the right$-$hand$-$side coefficient of the second constraint $($b$2)$ changes to $30?$

$(4)$ For what range of the objective coefficient of $x1($cl$)$ does the current optimal solution remain optimal?

$(5)$ If the objective coefficient of $x2($c$2)$ changes to $3\mathrm{.}5,$ find the new optimal solution $)$ and the new optimal objective value $(z).$