Find the full area of the triangle, and take away the area of the rectangle inside it to get the area of the shaded bits.
Area of whole triangle = (base x height) / 2 = (24 x 18) / 2 = 216
Area of rectangle = 6 x 20 = 120
Area of shaded region = 216 - 120 = 96
So 96 is the answer
