The number of btus that are needed to cool lucia’s apartment is 20,400 btus.
First step
Left side=12×10×20
Left side=2400 cubic feet
Middle =16×10×(20-9)
Middle =16×10×11
Middle =1,760 cubic feet
Right side=20×10×20
Right side= 4000 cubic feet
Second step
BTUs:
BTUs=(2400+1760+4000)×2.5
BTUs=8160×2.5
BTUs=20,400 Btus
Therefore the number of btus that are needed to cool lucia’s apartment is 20,400 btus.
Learn more about btus here:https://brainly.com/question/4260087