Composite solids are just a combination of simpler solids in disguise.
To find the volume of composite solids such as these:
The exception to these steps is when the solid we are looking at is more simply considered as a larger solid with a smaller solid cut out of it, like these ones.
In this case we would
Two holes are drilled through a rectangular prism as shown. Calculate the volume of the solid correct to one decimal place.
Find the volume of the figure shown, correct to 2 decimal places.