Question 780430
Area of North Wall = 30 * 66 = 1980 ft^2
Area of window = 5 * 7 = 35 ft^2
3 windows = 105 ft^2
1980 - 105 = 1875 ft^2
A gallon of paint will cover 375 ft^2
1875/375 = 5 
So, 5 gallons of paint are required.
Hope this helps.
:-)