47-12 1/3= 34 2/3 so the answer is 34 2/3 yards of fabric
        
                    
             
        
        
        
I think because she has more harder stuff
        
             
        
        
        
The best way to do this is to set up a proportion
30       20
----  = -----
0.5      x
then cross multiply and divide
20 × 0.5 = 10/30=1/3
he needs 1/3 tank of gas to drive 20 miles
I hope I've helped!
        
             
        
        
        
Yes he is correct. This is because if you convert all the fractions to be out of 10, the equation is 8/10 minus 5/10 equals 3/10 which is correct. if you have any more questions let me know. i hope this helps :)