Well, the area of a trapezoid is A = (
+
) * h * 1/2 so you can use the area of a parallelogram, which is A = l * w, by splitting the trapezoid into 2 triangles and one rectangle. So you'd use A = l * w for the rectangle and A = 1/2bh for the triangles. You'd get the same answer!
It is 3y because of the calculation being equivalent
5.5-3b = 2b-6.25
5.5+6.25 = 2b+3b
11.75 = 5b
11.75/5 = 5b/5
2.35 = b
Well 40 divided by 5 is 8 and you don't have options so I would say 8 loads a day :)