Adam descends 5 feet Multiply 5 by four and then you get 30 feet 
        
                    
             
        
        
        
you can answer it six point six six six six six infinity or you can answer it 6.7 depending upon how they want
 
        
             
        
        
        
In a short answer, to find average you need to add it all up and divide by the number of things you added. Ex. say I want to find the average for my english class, my grades are 90, 98, 100, 87, and 70. I would start by adding them up  to get 445. then since i have 5 grades, i would divide the sum 445 by 5 and get an 89 as my average. 
         
         (Everything in this answer is example only, not my real grades.)