What is the area in square units of the shaded region

The answer to your question is the letter D. 19.5 u²

Step-by-step explanation:

Process

1.- Calculate the Area of the rectangle ABCD

Area of a rectangle = base x height

                                 = (4 + 5) x 3

                                 = 9 x 3

                                 = 27 u²

2.- Calculate the area of the large triangle

Area of a triangle = base x height/2

-Substitution

Area of a triangle = (4 + 5) x 3/2

-Simplification

Area of a triangle = 9 x 3/2

-Result

Area of a triangle = 13.5 u²

3.- Calculate the area of the small triangle

Area of the triangle = 4 x 3/2

Area of the triangle = 6 u²

4.- Sum up the area of the triangles

Shaded area = 13.5 + 6 = 19.5 u²                  

a. she will receive a refund of $278.

step-by-step explanation: