Which shapes can be used in architecture? parallelograms
trapezoids
rectangles
triangles

The reason most commercial designs are rectangular, or square, is because they are easier, faster and more economical to build out of ordinary materials

The answer is rectangles! Sorry if wrong!

So here is the answer.
We represent h = hardwood and p = pine bark
Here is the equation: h + p = 176
2.75p + 3.50h = 520
Next, p = 176 -h (substitute)
2.75 (176-h) + 3.5h = 520
484 -2.75h + 3.5h = 520
3.5h-2.75h = 520 -484
0.75h = 36 (divide both by 0.75)
h = 48
Therefore, the number of hardwood sold is 48.
h + p = 176
p = 176-48
p= 128
The number of pine bark sold is 128.
Hope this helps.