Passengers enter an elevator of a building. The elevator moves up 6 floors, stops, moves down 5 floors, stops, and then moves up 7 floors and stops. the elevator is 2 floors from the top floor. Find the number of floors in the building when the passengers enter the elevator on the given floor. (a) If the passengers had started on the bottom floor, then the building has floors. (b) If the passengers had started on the middle floor, then the building has floors