We want to find the area of the rectangle. 
The area of a rectangle is given by; 

The length is x + 7 and the breadth is given by x + 5. 
Thus the area is; 

Therefore, the area is; 
 
 
        
             
        
        
        
25% — $40
100% — $40 * 4 = $160
The original price is $160.
 
        
             
        
        
        
X=width of the lake 
y=length of the lake.
we set out this system of equiations
x*y=9/20 
x=y/5
we solve by sustitution method
(y/5)*y=9/20
y²/5=9/20
y²=(5*9)/ 20
y²=2.25
y=√2.25=1.5
x=y/5
x=1.5/5=0.3
Solution:
width of the lake=0.3 miles
lenght of the lake=1.5 miles
        
             
        
        
        
Answer:
 the second option and x=20