An auditorium measures 35.0 m ✕ 25.0 m ✕ 9.0 m. the density of air is 1.20 kg/m3. (a) what is the volume of the room in cubic feet?

So we are asked the volume right?
The formula for volume is leangth multiplied by breadth multiplied by height right?
So as all the measurements are in correct units we do not have to convert them to a common unit.
So 35(leanght)*25(breadth) gives you 875.
Now 875 multiplied by the height (9) gives you 7875 right?
Now all we need to do is add the correct unit which ism meter Cubed
So the answer is 7875 m^3
Now I assume that you also have to calculate the amount of air in the auditorium.
So we are told that the density of air is 1.2 kg per m^3 right?
So there are 7875 m^3 of space and 1.2 kg of air is in one meter cubed.
So we multiply 7875 by 1.2 which gives us 9450.
So there are 9540 kg of air in the auditorium

38 dollars is your answer.