I got your answer! I will tell you right now. Your GCF is 9 and your LCM is 180! Your very much welcome!! Good luck for you! :)
        
                    
             
        
        
        
Answer: IDK hope you get a good grade :0 SORRY
Step-by-step explanation:
 
        
                    
             
        
        
        
The average speed = (speed 1 + speed 2)/2
the average speed = (80/10 + 100/20)/2
the average speed = (8 + 5)/2
the average speed = 13/2
the average speed = 6.5 km/minute