Answered

if hares with long legs run faster than hares with short legs, which hares do you expect would be most likely to survive and reproduce



Answer :

In this case, the hares with longer legs would be more likely to survive. This is due to the fact that hares are pretty defenseless creatures. Mostly, the one thing going for them to get away from predators is running, so the ones that run faster would then, logically, be more likely to survive long enough to reproduce, whereas the slow bunnies would get eaten before procreating. 
SchwarzschildRadius
Well,

In my opinion, a hare with longer legs than normal is an advantage.

Hares with longer legs are able to run faster.
  - As a result of being able to run faster, hares will be able to escape predators more easily.

Hares with longer legs are taller, and can therefore reach food more easily.

With these advantages, we would expect the hares with longer legs to survive and reproduce more than the hares with shorter legs.