If the numbers 2 11/12 and 3 7/9 are written in the form a/b which will have the greater numerator

You would have to turn them into improper fractions, after that you would have to see which one has the bigger number on top. To find the improper fraction:
2 11/12 = 2x12+11     3 7/9 = 3x9+7
             = 35/12                   = 34/9