Given the system of inequalities below, determine the shape of the feasible region and find the vertices of the feasible region. Give the shape as "triangle", "quadrilateral", "pentagon", or "unbounded". Report your vertices starting with the one which has the smallest $x$-value. If more than one vertex has the same, smallest $x$-value, start with the one that has the smallest $y$-value. Proceed clockwise from the first vertex. Leave any unnecessary answer spaces blank. Also give the value of the objective function $P = 1 x - 5 y$ for each vertex.

$$\begin{array}{l} x + y \geq 11 \cr 4 y - x \leq 8 \cr 5 x - y \geq 48 \cr x \geq 0 \cr y \geq 0 \cr \end{array}$$
The shape of the feasible region is (a) .

The first vertex is (,). $P =$
The second vertex is (,).$P =$
The third vertex is (,).$P =$
The fourth vertex is (,).$P =$
The fifth vertex is (,). $P =$