The floor is 1,872 square feet. The ceiling is also 1,872 square feet. In order to calculate the area of the walls, we would also need to know the height of the room.

It depends on whether "18 x 24" refers to 18 ft x 24 ft or 18 yards x 24 yards or 18 metres x 24 metres or some other measures. Since the units for the given measurements are not known, it is impossible to answer the question.

36 square feet on the floor. 36 square feet on the ceiling. ( 6 x height of the room) on each wall. Total area inside the room is [ 24 times (3 + height of the room) ] square feet.