Answer:
C 60π cm³
Step-by-step explanation:
1/3 x π x6² x 5
=60π
 
        
                    
             
        
        
        
Solution:-  Given that the total revenue function 
 ,where x is the number of rooms filled
 ,where x is the number of rooms filled
Now, differentiating the function w.r.t. x,we get
 
To find critical points ,Put 

 
        
             
        
        
        
3x+45 most u can simplify it
        
             
        
        
        
60,40,35,45,39
Put in order from least to greatest
35, 39, 40, 45, 60
Range = Max - Min
Range = 60 - 35
Range = 25
Answer
D) 25