What will be the time at Greenwich meridian when it is 12 noon at longitude 60$^0$E

Analyze the question: We are given the local time at 60°E (12 noon) and asked for the time at Greenwich (0°).

Concept:

• The Earth rotates 360° in 24 hours, so 15° of longitude = 1 hour (or 1° = 4 minutes).
• Places east of Greenwich are ahead in time (the sun rises there first).
• Places west of Greenwich are behind in time.

Solution:

1. Longitude difference = 60° − 0° = 60°
2. Time difference = 60° ÷ 15° = 4 hours
3. Since 60°E is east of Greenwich, its time is ahead of Greenwich's time. So Greenwich is 4 hours behind 60°E.
4. Greenwich time = 12:00 noon − 4 hours = 8:00 a.m.

Answer: Option C, 8.00 a.m.

Tip: Remember "East is Earlier in the day, so Greenwich is Less"; in other words, East = Add, West = Whittle (subtract) when going from Greenwich to another place. Here we're going the other way, from 60°E back to Greenwich, so we subtract. Always ask: "Is my target place east or west of the known place?" A quick check is to see if your answer makes sense. Greenwich is to the west of 60°E, so it must be earlier than noon, which rules out the p.m. options (B and D).