Here's why:

* Prime Meridian: The Prime Meridian is a line of longitude that runs from the North Pole to the South Pole, passing through Greenwich, England. It is designated as 0 degrees longitude.

* Longitude: Longitude lines run vertically around the Earth, with values increasing from 0 degrees at the Prime Meridian to 180 degrees East or West.

Since 15 E is only 15 degrees away from the Prime Meridian, while 60 W is 60 degrees away, 15 E is much closer.