I would not know the answer to this question sorry
        
             
        
        
        
Answer:
9
Step-by-step explanation:
Let's say Mark is M and his brother is B.
M+5=B
M+B=23
Now we can solve using subsitution.
M+M+5=23
(Subtract 5 from both sides)
2M=18
M=9
Hope this helped!
 
        
             
        
        
        
The volume is the product of the height and the area of the base.
  V = Bh
The area of the square base is (4 cm)² = 16 cm², so the height can be found from
  144 cm³ = (16 cm²)h
  h = (144 cm³)/(16 cm² = 9 cm
The height of the prism is 9 cm.