To determine the time zone offset from longitude, which operation is used?

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Multiple Choice

To determine the time zone offset from longitude, which operation is used?

Time zones align with 15-degree steps because the Earth rotates 360 degrees in 24 hours, so each hour corresponds to 15 degrees. To turn a longitude into a time offset in hours, you convert degrees to hours by dividing the longitude by 15. Rounding to the nearest hour (as done in standard practice) maps that longitude to a practical time zone offset. For example, a longitude of 30 degrees east gives 30/15 = 2 hours ahead of UTC, while 30 degrees west (negative) gives -2 hours. The other operations don’t reflect how time offsets are derived: multiplying by 15 would produce degrees from hours, not hours from degrees; dividing by 24 isn’t tied to the 24-hour day in this context; and simply adding 15 to longitude has no relation to time zones.

Time zones align with 15-degree steps because the Earth rotates 360 degrees in 24 hours, so each hour corresponds to 15 degrees. To turn a longitude into a time offset in hours, you convert degrees to hours by dividing the longitude by 15. Rounding to the nearest hour (as done in standard practice) maps that longitude to a practical time zone offset. For example, a longitude of 30 degrees east gives 30/15 = 2 hours ahead of UTC, while 30 degrees west (negative) gives -2 hours.

The other operations don’t reflect how time offsets are derived: multiplying by 15 would produce degrees from hours, not hours from degrees; dividing by 24 isn’t tied to the 24-hour day in this context; and simply adding 15 to longitude has no relation to time zones.

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