Answer:
b.332.2
Step-by-step explanation:
 
        
             
        
        
        
42/6 = 7 105/15 = 7
Biggest common factor is 7. 
not sure if that was the question
        
                    
             
        
        
        
I believe the answer is 3
        
             
        
        
        
You first need to know how much miles it takes on the trail. Then you look 20 x 3 is one hour. And if the 3 group said it takes 2 hours waking for them its like this, the first group takes one hour to go thru the trail, but the second group takes and hour and half the 3 group takes 2 hours.
I wish this helps. :)