Are you trying to figure out what we would think of your gf/sister's lifts before you tell us what they are to see if we would be impressed? (I'm bitchy again and saw some of your post history...)
Anyways, assuming the "average woman in mid 20's" knows where the gym is (which is not an accurate assumption, but regardless...), she most likely is familiar with the cardio equipment and maybe the light dumbbells. Therefore, I'm not impressed by anything she does and wouldn't waste my time trying to figure out a 5RM for her because she'd think it would make her bulky.
NOW, let's assume by "average woman in mid 20s" you mean one that is actually serious about lifting and has good form (ie. No quarter/half squats). Or at least not opposed to lifting heavy. As a raw 1RM, I would be impressed (used loosely here) with 185/100/225.
As for a 5RM, I would suggest you pick a weight, get them to do as many good reps as they can do and adjust accordingly. It's all relative to their strengths/weaknesses.
That's my snarky post for the day. I'm going back to working...