Calculate the volume of the rectangular prism on top if the volume of the composite shape is 800 cu units.

The correct option is A 200 cu units
Volume of the prism at the bottom
= $15\times 8\times 5$
= 600 cu units

Volume of the entire solid
= 800 cu units

But, volume of the entire solid = volume of the prism on top + volume of the prism at the bottom.

$\therefore$ 800 cu units
= Volume of the prism on top +
600 cu units

$\therefore$ Volume of the prism on top
= 800 cu units - 600 cu units
= 200 cu units