Answer:
Step-by-step explanation:
 
        
             
        
        
        
B is 26
c is 15 
X is 80
g is 30
x is -5
W is -4
r is 45
k is 12
f is 50
        
             
        
        
        
The top 4 firms have (23 +22 +18 +12)% = 75% of the market.
The 4-firm concentration ratio is 0.75 or 75%.
        
             
        
        
        
K = Kevin's age
D = Daniel's age
K = 3D
K - 4 = 5(D - 4)
Plug in 3D for the K values in the second equation.
3D - 4 = 5(D - 4)   Use the Distributive Property
3D - 4 = 5D - 20   Add 4 to both sides
     3D = 5D - 16     Subtract 5D from both sides
    -2D = -16            Divide both sides by -2
       D = 8 
 Now, plug that D value into the original equation.
K = 3D    Plug in the D value
K = 3(8)   Multiply
K = 24
Finally, you can double check your math.
4 years ago, Daniel would've been 4 and Kevin would be 20, so Kevin would've been 5 times as old as Daniel.  And 8 x 3 = 24.
So, Kevin is 24.
        
                    
             
        
        
        
8x4x11 - (4x1x3)
352 - 12
= 340
The answer is 340yd^3