To find volume, you multiply length * width * height.
In this case, break up the figure into pieces you know, since as a base rectangle and a top rectangle.
base rectangle: 350 = 10 ( length ) * 7 ( width ) * 5 ( height )
upper/top rectangle: 126 = 3 ( l ) * 7 ( w ) * 6 ( h )
350 + 126 = your answer
