10 9/10.... because 10 can be divided into 109 10 whole times with a remainder of 9 so you put the 9 over the original denominator which is 10 so 9 over 10
        
                    
             
        
        
        
2/5 (x-4)=2x   answer is x= -1
        
             
        
        
        
Cookies : 9, 18, 27, 36, 
Ice cream: 12, 24, 36
So in 36 days.
        
                    
             
        
        
        
(a) You can plant 7 1/4 acres per pound of seed
(b) Isabel takes 7 minutes to run a mile