The navigator aboard a ship at approximately...

Question 1 of 2707066636ee928f7522a1c519cd9

The navigator aboard a ship at approximately 165°E longitude observes the Sun at ZT 14-25-04 on 21 September. What is the GMT and Greenwich date of the observation?

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Question 1 of 27070

The navigator aboard a ship at approximately 165°E longitude observes the Sun at ZT 14-25-04 on 21 September. What is the GMT and Greenwich date of the observation?

🔍 Key Concepts

• Zone Description (ZD) based on longitude (15° per hour, east vs west) • Relationship between Zone Time (ZT), Greenwich Mean Time (GMT/UT), and ZD • How changing time zones can change the date at Greenwich

💭 Think About

• First, determine which standard time zone a ship at 165°E would normally use. How many whole 15° zones away from Greenwich is that? • Next, decide the correct sign of the ZD for an east longitude using the standard USCG formula that links ZT and GMT. • After converting ZT to GMT, check whether you cross 0000 at Greenwich, and if so, in which direction the date changes.

✅ Before You Answer

• Verify the ZD magnitude: 165° ÷ 15° = 11 hours (don’t round incorrectly). • Confirm the formula you are using: is it GMT = ZT + ZD or GMT = ZT − ZD under the USCG convention? Make sure the ZD sign is consistent with that formula. • After you get GMT in hours, check if it is greater than 24 or less than 0; if so, adjust by ±24 hours and change the Greenwich date accordingly before choosing the answer.