Final answer:
When you travel west of the Prime Meridian, the time decreases. For every 15 degrees you travel west, the time is decreased by one hour.
Step-by-step explanation:
When you travel west of the Prime Meridian, the time decreases. The Earth is divided into 360 degrees of longitude, and for every 15 degrees you travel west, the time is decreased by one hour.
For example, if it is 12 noon at your current location and you travel 45 degrees west, the time would be 9 a.m. Since there are 24 time zones in the world, you would need to adjust the time accordingly when traveling west.