Answer:
Number of cheaper dresses sold  is 35
Number of expensive  dresses sold  is 15
Step-by-step explanation:
Given:
Cost of cheaper dresses = $90
Cost of  expensive dresses = $140
Total cost of  the dresses = $5250
To Find:
Number of cheaper dress = ?
Number of expensive  dress = ?
Solution:
Let 
The number of  cheaper dresses be x
The number of  expensive dresses be y
(Number of cheaper dresses X cost of cheap dress) +  (Number of Expensive dresses X cost of  expensive dress)  =  $5250
 =  $5250
=  $5250
It is given that the 20 more of the cheaper dresses than the expensive dresses is sold 
So, 
 number of cheaper dress  =  20  +  number of expensive dress
x = 20 + y---------------------------------------(1)







y = 15
Substituting y in (1)
x = 20 +15
x= 35
 
        
             
        
        
        
Answer: 
Step-by-step explanation: 





 
        
             
        
        
        
8*(n+6)=80
distribute
8n+48 = 80
subtract 48 from each side
8n = 32
divide by 8
n=4
 
        
                    
             
        
        
        
Answer: 68.1
Step-by-step explanation:
The area of a semi-circle is 1/2 the area of a full circle. The area of a full circle is pi*r^2. Therefore, the area of a semi-circle is:


The area of a rectangle is the length multiplied by the width:


The net area is the sum of the rectangle and the semi-circle:

 
        
             
        
        
        
5 because it’s a double negative which offsets the answer to be positive 5