In order to compare the distances rowed, we need to come up with a common denominator. Our least common denominator is 8 because 2 and 4 are both divisors of 8.
Laura rowed 7/8 mile
Daniel rowed 4/8 mile ()
Annabelle rowed 2/8 mile ()
Daniel and Annabelle rowed a combined 6/8 mile (). 7/8 is greater than 6/8. Laura rowed a distance greater than the combined distance of Daniel and Annabelle.