Answer:
The volume of the mulch is
![528\ in^(3)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/lylsa0qeioakrviucmi88x8v85mfddp0qy.png)
Explanation:
we know that
The volume of the mulch is equal to
![V=Bh](https://img.qammunity.org/2020/formulas/mathematics/college/1z8biyc5dxidzjd7gaahhzli35rckolci0.png)
where
B is the area of the border of the mulch
h is the deep of the mulch
Find the area of the border B
The area of the border B is equal to the area of the complete square minus the area of the inside square
so
![B=24^(2)-20^(2) = 176\ in^(2)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ipzviietu7al9q7eurm8qkzfjz6n35vavb.png)
we have
-----> the deep of the mulch
substitute the values
![V=(176)(3)=528\ in^(3)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/iko3ldln40v8bly8x7w2l69xrk8mvmxgqn.png)