If it is 1:00 P.M. EST in Washington, D.C., what is the time in Denver, Colorado, the longitude of which is 30° more westerly?
A) 9:00 A.M. MST
B) 11:00 A.M. MST
C) 3:00 P.M. MST
D) Noon. MST

Question

Quizplus · Accepted Answer

Each hour in time difference corresponds to 15 degrees of longitude because a full rotation of the Earth (360 degrees) takes 24 hours. Since Denver is 30 degrees more westerly than Washington, D.C., this corresponds to a 2-hour difference (30/15=2). Since Washington, D.C. is on Eastern Standard Time (EST) and Denver is on Mountain Standard Time (MST), which is 2 hours behind EST, it would be 11:00 A.M. MST in Denver when it's 1:00 P.M. EST in Washington, D.C.

If It Is 1:00 P