Apainting contractor paints with a brush at a rate of 192 square feet per hour. using a paint sprayer, she is able to cover 576 square feet per hour. she has a contract to paint a house with 1632 square feet of wall surface and 2400 square feet of ceiling space. she estimates she has 3 hours of brushwork to perform. how many hours will she need to use the sprayer in order to complete the job?