You can scale the magnitudes by a common factor. Try working out the same problem with TAS 236 kt (472 kt / 2) and wind 25 kt (50 kt / 2).
Without correcting for drift the GS should work out as 243 kt so simply multiply by 2 to get 486 kt. If correcting, GS 241 kt * 2 = 482 kt.
Last edited by selfin; 16th March 2010 at 17:18.
Reason: Question appears to require GS without applying correction for drift.