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?

876 square feet need to be painted.

Step-by-step explanation:

There are four walls in each bedroom, since she can't paint floors or ceilings. So we calculate the number of square feet of wall there is in one bedroom

(12*8) + (12*8) + (10*8) + (10*8) - 60=160+192-60=292

There are 3 bedrooms so

292*3=876