Answer:
7.5
Step-by-step explanation:
Divide 30 by 3.99
 
        
             
        
        
        
The volume a cylinder is v=(area of base)h and since the area of the base is πr², you can write the equation a v=πr²h.  Since the problem wants us to find what be is in the equation of a cylinder as v=Bh, we know that B=πr².  The problem gave us the diameter of the circle so we no the radius is going to be the diameter (24) divided by 2 which equals 12.  therefore B=12²π.
I hope this helps. 
        
             
        
        
        
I think you have to divide 80milion and 84