On 10 August your 0430 ZT position is LAT 29°56.7' S, LONG 139°11.0' E. Your course is 321°T, speed 18.2 knots. You observed 3 celestial bodies. Determine the latitude and longitude of your 0500 running fix.

Correct Answer: Option D — LAT 29°49.2'S, LONG 138°57.0'E

Advancing celestial lines of position along the DR track for the specified time interval provides the running fix. Course and speed vectors correctly translate previous observations to the updated fix time.