Your longitude is 124°E, and your local mean...

🔍 Key Concepts

• Longitude time conversion: every 15° of longitude equals 1 hour of time difference • East vs. West longitudes: how local time relates to Greenwich Mean Time (GMT/UT) when you are east of Greenwich • Date change: when adding or subtracting hours, check if you cross midnight and change the calendar date

💭 Think About

• First, convert 124° of longitude into an equivalent number of hours and minutes of time. How many full 15° segments fit into 124°, and what is the remainder? • Since you are at 124°E, is your local mean time ahead of or behind Greenwich time? Based on that, should you add or subtract the longitude time from your local mean time to get Greenwich time? • After adjusting the time, did you cross 0000 or 2400? If so, what happens to the date at Greenwich compared to your local date of the 5th?

✅ Before You Answer

• Confirm the time difference between local meridian (124°E) and Greenwich (0°) in hours and minutes before touching the multiple-choice answers • Double-check the direction of time correction (add vs. subtract) for an easterly longitude when going from Local Mean Time (LMT) to Greenwich Mean Time (GMT) • Verify whether the date at Greenwich should be the 4th or the 5th after your time correction, before choosing an option

Your longitude is 124°E, and your local mean time is 0520 on the 5th of the month. Which is the mean time and date at Greenwich?

2104 on the 4th

1336 on the 4th

2104 on the 5th

1336 on the 5th

🔍 Key Concepts

💭 Think About

✅ Before You Answer