Where’s the model? If it says choose a model, there should be a model
        
                    
             
        
        
        
Answer:
33.3
Step-by-step explanation:
 
        
             
        
        
        
Replace the words with what you know 
(Original cost)(6%)=5.25
(Original cost)(0.06)=5.25
(original cost)=5.25/0.06=87.5
        
                    
             
        
        
        
<span>given:
   bull's eye radius= x
 width of surrounding rings=y
   solution:
   Radius of the circle=x+4y
Area of the outermost ring=Area of the circle-Area of the penultimate ring
=Ď€(x+4y)^2-Ď€(x+3y)^2
=Ď€(x^2+8xy+16y^2-x^2-9y^2-6xy)
 =Ď€(2xy+7y^2)
 hence the area of the outermost ring in terms of x and y is Ď€(2xy+7y^2).</span>
        
             
        
        
        
Answer:
25 
Step-by-step explanation:
We require to solve for n, hence
 n(n + 1) = 325
 n(n + 1) = 325 
multiply both sides by 2 to eliminate the fraction
n(n + 1) = 650
n² + n = 650
subtract 650 from both sides to have equation in standard form
n² + n - 650 = 0 ← in standard form
(n + 26)(n - 25) = 0 ← in factored form
equate each factor to zero and solve for n
n + 26 = 0 ⇒ n = - 26
n - 25 = 0 ⇒ n = 25
however, n > 0 ⇒ n = 25