painting 12 rooms finding the total cost of paint needed to cover the room with 2 coats

Question

Suppose a gallon of latex paint costs $31.00 and can cover 350 sq ft. There are 12 rooms that are needed to be painted with 30ft x 15ft with a 9 ft high ceiling. In each room all four walls and the ceiling need painting (but not the floors) and each room will need two coats of paint. How much will you have to spend on paint, ignoring windows and doors? 

Answer 1

Each room breaks down like this:

  One wall:  15 x 9 = 135

  Other wall: 30 x 9 = 270

  Ceiling: 30 x 15 = 450

So each room is 135 + 270 + 450 = 855 square feet

 

855 x 12 x 2 = 20520 ft

 

(20520 / 350) =  59 cans of paint (rounded)

59 * $31 = $1829