What is the longitude of a place X whose time is noon when Greenwich meantime is 6p.m?
Answer Details
The earth rotates 360 degrees in 24 hours, which means that it rotates 15 degrees per hour. The time difference between Greenwich meantime and Place X is 6 hours. Therefore, the difference in longitude between Greenwich and Place X is 6 x 15 = 90 degrees. Since the time at Place X is 12 pm (noon), we know that it is halfway between sunrise and sunset, which means that it is roughly at the meridian line of that location. Therefore, we can calculate the longitude of Place X by adding or subtracting half of the 360-degree circumference of the earth from the longitude of the Greenwich meridian (which is 0 degrees). Since the time difference between Greenwich and Place X is westward (Greenwich time is ahead of Place X time), we need to subtract 90 degrees from the Greenwich meridian to get the longitude of Place X, which is 90 degrees west, or 90°W. Therefore, the correct answer is option (E) 90°W.