Given :
If 2000 ft³ of air is crossing an evaporator coil and is cooled from 80°F to 60°F.
To Find :
The volume of air in ft³ exiting the evaporator coil.
Solution :
We know, relation between initial and final temperature and volume is given by :

Here, temperature is in Kelvin .
We know, Kelvin temperature is given by :

Putting F = 60° F,

Putting F = 80° F,

Putting all values, we get :

Hence, this is the required solution.