AMC 12 2007b Problem 1

Isabella's house has 3 bedrooms. Each bedroom is 12 feet long, 10 feet wide, and 8 feet high. Isabella must paint the walls of all the bedrooms. Doorways and windows, which will not be painted, occupy 60 square feet in each bedroom. How many square feet of walls must be painted?

$\mathrm{(A) \ } 678 \mathrm{(B) \ } 768 \mathrm{(C) \ } 786 \mathrm{(D) \ } 867 \mathrm{(E) \ } 876$