What is the time in Accra at longitude 0° when the local time at longitude 45°W is 12noon?

Analyze the question: We need the time at longitude 0° (Accra, on the Prime Meridian) when it is 12 noon at 45°W.

Concept:

• The Earth rotates 360° in 24 hours, so 15° = 1 hour (or 1° = 4 minutes).
• Places east of a given location are ahead in time (they see the sun first).
• Places west are behind in time.

Solution:

1. Difference in longitude = 45° − 0° = 45°
2. Time difference = 45° ÷ 15° = 3 hours
3. Longitude 0° is east of 45°W, so it is ahead in time.
4. Time at 0° = 12:00 noon + 3 hours = 3:00 pm

Answer: The time in Accra is 3:00 pm, which is option A.

Tip: Remember "East is least... no, East is ahead!" A simple memory trick is "East = Earlier sunrise = Add time; West = Warlier (later) = Withdraw (subtract)." Always find the longitude difference, divide by 15, then add if you are moving east and subtract if you are moving west.