Figure on top is 8 times 9 (to find volume)
the figure on top has a volume of 72 cm<span>^3
the volume of the lower figure:
3 times 9 times 5 = 135 cm</span><span>^3
72+135=207 cm</span><span>^3
the volume of both figures is 207 cm</span><span>^3</span>
6P3 => 6!/(6-3)! = 120.
I can't very well explain, but I hope it works.
I'd say by rounding and similar techniques the answer is 468, though it doesn't say all the needed numbers.