Question

2. When the local time is 6am on Monday at Alexandria30°E in Egypt,what will be the local time at New Orleans90°W in the United States? ​

Answer 1

Explanation:

The 120º longitude difference is 1313 the circumference of Earth. Since 1313 of 24 hours is 8 hours, it “should be” 10 p.m. on the previous day in New Orleans.

However, governments don’t use strict geographic time zones. In the case of Alexandria and New Orleans, the 8 hour difference happens to be accurate between the first Sunday in November and the second Sunday in March.

That’s probably why the writer of the question chose those two cities. Kashgar and São Luís are also 120º apart, and São Luís is 11 hours behind. Apia and Pago Pago are 1º apart and Apia is 25 hours ahead.

Going back to Alexandria and New Orleans, the reason is law. The government of the Arab Republic of Egypt observes a time offset of UTC+02:00 year-round, and the government of the United States of America has drawn New Orleans into its Central Time Zone, which observes a time offset of UTC-06:00.

2−(−6)=82−(−6)=8, so the answer to your question is 10 p.m. right now.

Between the second Sunday in March and the first Sunday in November, the United States observes Daylight Saving Time, so New Orleans moves to UTC-05:00.

2 - (-5) = 7, so the answer to your question is 11 p.m. for most of the year.