Example $3\mathrm{.}6-1($Changes in the Right$-$Hand Side$)$

JOBCO manufactures two products on two machines. A unit of product $1$ requires $2$ hours on machine $1$ and $1$ hour on machine $2.$ For product $2,$ one unit requires $1$ hour on machine $1$ and $3$ hours on machine $2.$ The revenues per unit of products $1$ and $2$ are $$30$ and $$20,$ respectively. The total daily processing time available for each machine is $8$ hours.