Geographic Grid: Latitudes and Longitudes — Geography STD 9 — Question

Large countries like Russia, Canada, and the United States have vast longitudinal extent. They do not have a single Standard Time for the whole Country. They have many time zones, with each time zone covering about 15° of longitude. The erstwhile Soviet Union had 11 times zones to cover 165° of longitudinal extent. Canada and the United States have five time zones extending from the Atlantic coast of the Pacific coast. There is a time difference of five hours between the two coasts.