I still think, with the NDB at right angles to the aircraft track, the RBI needle points at 274.
Incidentally, I find it helps to imagine the RBI mounted horizontally so that the RBI card "rotates underneath the fixed needle". After all, the needle always points at the NDB, only you and the aircraft are rotating.
Take the no-wind case first.
360 on the RBI represents straight ahead, which will be in the track direction (no wind).
The NDB is on the left, and at right angles to the track, so it is on the wingtip, the needle points to it and is on 270.
We don't need to know the track to work this out. The 170 info is a red herring.
Now rotate the aircraft 4 degrees to the left because of the wind correction angle.
The NDB is in the same place, the aircraft is in the same place, the track has not changed, all we did was rotate the card 4 degrees under the needle. The needle now points at 274.
We still didn't need to know the track!