If a clock is set to Greenwich Mean Time and the Sun is observed to reach its zenith at 10:00 A. M., what is the longitude?

The answer to the question is

30 ° east of Greenwich Mean Time

Step-by-step explanation:

To solve this we have the given variables

Current Greenwich Mean Time = 10.00 AM

Location of the Sun at the current longitude = zenith

Supposed correct time when clock is at zenith = 12 noon or 12.00 pm

Time difference, or correction required = 10.00 a. m. - 12 p. m. = 2 hours leading

As there are 24 hours in a day one hour of the difference in time is equivalent to 360/24 or 15 ° and as the Sun is already at its zenith at the location then the location is eastwards of Greenwich Mean time that is,

15 ° * 2 = 30 ° east of Greenwich Mean Time