I honestly don't know any of this so
        
                    
             
        
        
        
Answer:
Part A: 480 ounces of water are left in the water tank.
Part B: he will drink 3 tanks of water in 30 days.
Step-by-step explanation:
Part A: 
5x8x16 = 6x16 = 1/2x8x16
=640 = 96 = 64
=480
Part B:
4x30 divided by (5x8) = 120 divided by 40 = 3
 
        
             
        
        
        
Answer:
It will grow 37.5 inches
Step-by-step explanation:
It grew 7.5 in 3 weeks. Divide 7.5 by 3 and you'll get 2.5. So that means every week it grows 2.5 inches. So multiply 2.5 x 15 and you'll get 37.5 inches