Let's break this down into four steps from the start point
60°00'N 030°00'W.
1 degree along any meridian = 60 NM, i.e. 1 minute of arc = 1 NM.
Therefore, 3600 NM along a Meridian = 3,600' = 60°
60° South of 60°00'N = 00°00'N/S, which is the Equator
Position = 00°00'N/S 030°00'W
1 degree along the Equator= 60 NM, i.e. 1 minute of arc = 1 NM.
Therefore, 3600 NM along the Equator = 3,600' = 60°
60° East of 030°00'W = 030°00'E
Position = 00°00'N/S 030°00'E
1 degree along any meridian = 60 NM, i.e. 1 minute of arc = 1 NM.
Therefore, 3600 NM along a Meridian = 3,600' = 60°
60° North of the Equator = 60°00'N
Position = 60°00'N 030°00'E
Now for the bit which catches people out.
Distance along any Line of Latitude, except the Equator, requires application
of the Departure formula, which calculates the distance along a Line of
Latitude:
Departure = Change of Longitude (in minutes of arc) x Cosine of the Latitude
In this case, we have been give the Departure distance, 3600 NM and we have to
convert that into an angular change of longitude.
Departure = Change of Longitude (in minutes of arc) x Cosine of the Latitude
3600 = ChLong (') x Cosine 60°00'N
3600 = ChLong (') x 0.5
ChLong (') = 3600 / 0.5
ChLong (') = 7,200'
7,200' / 60 = 120°
120° West of 60°00'N 030°00'E = 60°00'N 090°00'W
Final Position = 60°00'N 090°00'W