You didn't provide a picture, but if your problem is like the one in my workbook, I might be able to help.
Find the volume of the first figure, then find the volume of the second figure, then add them together.
V=lwh
V(1)=(15)(12)(6)
= 1,080in^3
V(2)=(12)(6)(6)
= 432in^3
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1,080+432= 1,512 in^3
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Your answer should be 1,512
