Answer: 1947 square inches.
Explanation:
We know that the area of a regular polygon is given by :-

The perimeter of the hexagon =

Apothem = 9.5 in.
The area of the top or bottom of the prism is given by :-

Area of the 6 faces around the prism having each of width 11 in. , and length of 20 in.=

Now, the total surface area of the given prism :-

Hence, the surface area of the given prism = 1947 square inches.