Smithpa,
.5/100*1000 + 1/100*2000 + 1.5/100*3000 + 2/100*4000 = 150
The thing to be understood on this problem is the calculation of the successive increase in percents for the amonuts obtained by the differences in the revenie banding.
i.e .5 percent on the first 1000 dollars
1 percent not on 3000$ but 3000-1000 = 2000$ etc....
Hope this helps!