I'm currently enrolled in an HVAC apprentice program and as a bonus assignment, the instructor gave us a formula and asked us to find its meaning and application.
Try as I might though, I couldn't find anything in my books or on the internet on this formula.
Does anyone here have even a general idea what this formula is and what it's used for?

Q =
q
--------------------
(Tr-To)(60P Cp)


Q = Ventilation Rate - CFM
q = Room Heat - Btu/hr
Tr = Allowed Room Temp - Farenheit
To = Outside Air Temp
P = Air Density - Lb M/Feet cubed
Cp = Specific Heat of Air = 0.24 Btu/lb M Farenheit