I’m self-studying for the upgrade from 100T to 500T and have been stuck on a few problems. I’ve exhausted all of my resources and hope that someone out there is willing/able to explain how to solve one of these problems. The problems are all looking for compass deviation given various celestial information, and I think my problem may lie with not having the necessary materials in my home to study for this. Anyway, one of the questions is:

On 1 September your 11115 zone time DR position is LAT 25 20.0’N, LONG 28 24.0’W. At that time, you observe the Sun bearing 160.5psc. The chronometer reads 01h 14m 58s, and the chronometer error is 01m 17s fast. The variation is 13.5W. What is the deviation of the standard compass? The correct answer (according to the guide) is 2.1E.

This test (more specifically, these few problems) are all that stand between me and the 500 ton near coastal. Any information you have would be greatly appreciated.

Thanks.