IMO E.
I actually solved this one using POE. It took me 10 seconds, but I would still prefer Bunuel approach

. Not sure if many ppl will like it but in case
we are pressed for time, we could try this approach.
A. 65+55/(x-y) => (mi/hr) / hr will not give you distance in miles any how.
B. 65y+55x/(x-y) => (mi/hr) will not give you distance in miles
C. (65/y) + (55/x) => Same as A
Now we have only 2 options D & E. We already know that (x>y) , therefore y-x<0. This implies that 65(y-x)+55(x-y) <0 and distance can never be less than 0 as we consider it as an absolute quantity here.
Left is option E which looks reasonable and hence
IMO E.
Hope this helps!!