• Yeah, that's confusing.  I think they mean the rear (which has a 25' setback) fronts a public way, but it's unclear. It makes sense that the 25' setback would be used for the public way though.

Hope this helps!

Rebekka, www.stepuparchitecture.com

• This is super confusing because, as I think you are pointing out, there is a 50 foot side and a 100 foot side but no 25 foot side…maybe as others have said, this question is deeming the back side, with its 25 foot setback as the “25 foot side”…or maybe it’s a typo left over from a cut-and-paste and they meant to suggest this is a corner or through lot (through lots touch the street on front and back yards)…argh.
In any event I suspect that the right-of-way adjacency is a “test item distractor”…in most of these narrative questions you’ll be given a bit more information than is necessary to answer. I guess the thought is that in practice you often know more about a project than is necessary to solve some problem.
Some zoning ordinances measure setbacks from public rights-of-ways, though this one doesn’t. For example, I found the following ordinance
Minimum front setback requirements consist of two (2) distances:
Thirty-five (35) feet is the required distance from the road right-of-way if the right-of-way is fifty (50) feet or greater; or
Sixty (60) feet is the required distance from the centerline of the road if the right-of-way is less than fifty (50) feet.