OK...
Draw a picture with an aeroplane exactly West of an NDB (aeroplane right angle to the NDB), on the 270 radial heading South, 180. The ADF needle (RBI) is pointing left at 270 on the compass card because ADF needles always point at the NDB. A fixed card ADF will always have 360 (North) at the top, and to be honest I usually leave my movable card ADF set to North too unless its needed for something specific.
Now turn the aeroplane to head 170 i.e. 10 degrees to the left. The RBI needle appears to move up toward the top of the compass card onto to 280. That is to say the needle rises. In fact the needle has remained constant relative to the compass card and NDB, and it's the aeroplane that has moved.
Now for the drift. 4 degrees of starboard drift means you turn 4 degrees into wind i.e. 4 degrees left in this case. So the aeroplane is now heading 166.
If the aeroplane is heading 166 on the 270 radial from an NDB, the RBI needle will point a further 4 degrees toward the top of the compass card onto 284.
All of the numbers are magnetic as the heading was given in magnetic and nav aids (VOR/NDB/RBI/RMI/HSI) are all magnetic too. There is no mag deviation, variation, or any other 'ation' in this question therefore assume that it doesnt require any working out other than the above.
These are all subtly different and will therefore change the answer:
- aeroplane at a right angle to the NDB (NDB radial 270 + track 170 + drift 4 = heading 166 = RBI 284)
- NDB at a right angle to the aeroplane (on the wingtip (i.e. heading 166 = NDB Radial 256 = RBI 270)
- NDB at a right angle to track (170 = RBI 270 = NDB radial 260 (+ 4 drift = hdg 166 = RBI 274))
It is a poorly worded question by all accounts and I would agree with BPF if the NDB was at right angles to the aeroplane. It's a very subtle difference and there are no questions this finnicky in the IMCr exam thankfully!
Hope that clears it up.
GW