The exercise is given here: tripleintx.htm.

Once the assignment is complete, look for the solution here: [pdf, mw]

Remember, to iterate a triple integral, you have to go through a thought process to get the limits of integration correctly, i.e., to parametrize the 3d region as set of points bounded by a succession of functional relationships. This annoted diagrammatic approach is the only clear way that you can analyze this process and communicate it unambiguously to yourself and others (like bob).