The volume of the rectangular prism can be found with the formula
v= length × width × height
V = 10×10×30 = 3000
the volume of the triangular prism can be found with
v = 1/2(base×width×height)
v=1/2×30×9×10 = 1/2×2700
v = 1350
Now add the two volumes together for the total volume...
3000+1350 = 4,350 in^3
