Answer:
A) 
Step-by-step explanation:
The equation of a circle is  where
 where  is the center and
 is the center and  is the radius. If
 is the radius. If  and
 and  , then:
, then:

Therefore, the equation of the circle is 
 
        
             
        
        
        
Try this solution:
1. if 1st number is 'x', the 2d number is 'y', then it is possible to make up the system of two equation according to the condition:

2. one number is 11, another number is 10.
 
        
        
        
Answer:
4.5 minutes per 1 lap. 
Step-by-step explanation: