Time and Clocks

This question reflects a specific point in time - Russia had 11 time zones from 2010-2014. Russia has since reduced to 9 time zones (2014-), and currently has 11 again (since 2016). When this question was written, 11 was correct.

Indian Standard Time (IST) is calculated based on the 82.5°E longitude, which puts it exactly 5 hours and 30 minutes ahead of Greenwich Mean Time (GMT). Therefore, IST is GMT + 5:30. The other options incorrectly suggest being behind GMT or using a 6-hour offset.

The time until they chime together again is the Least Common Multiple (LCM) of 18, 24, and 32. 18=2*3^2, 24=2^3*3, 32=2^5. LCM = 2^5 * 3^2 = 32 * 9 = 288 minutes. 288 minutes is exactly 4 hours and 48 minutes.

A mechanical wind-up alarm clock does not distinguish between AM and PM. If set to 9, it will ring at the first 9 o'clock it reaches, which is 9 PM, just one hour later.

A red blood cell typically takes about 20 seconds to complete one full circulation through the human body. This impressive speed allows blood to deliver oxygen and nutrients efficiently to all tissues. The circulatory system is remarkably fast, pumping blood through the entire body in just one-fifth of a minute.

When hard-boiling eggs, you cook them together in the same pot. The cooking time depends on the eggs themselves, not the quantity (as long as the pot is large enough). Four eggs cooked simultaneously will take the same 20 minutes as one egg.

IST is 5 hours 30 minutes ahead of Greenwich Mean Time (GMT). When it is noon in London, it is 5:30 PM in India. This offset is due to India's central longitude being 82.5°E, which is 5.5 hours ahead of the Prime Meridian.

Indian Standard Time (IST) is UTC+5:30, which is 5 hours and 30 minutes ahead of Greenwich Mean Time (GMT). India uses a half-hour offset rather than the full-hour offset used by most time zones. The question's '-5:30 GMT' likely means '5 hours and 30 minutes ahead of GMT' or is possibly showing the offset incorrectly.

Let's work backwards: 2 hours ago it was 7 o'clock. At 7 PM, it is 6 hours after 1 PM and 6 hours before 1 AM, so the condition is satisfied. Therefore it is now 9 o'clock. The time symmetry works because 7 PM is exactly halfway between 1 PM and 1 AM.

If the correct time is 8:45: Clock 1 (9:05) is 20 mins fast. Clock 2 (8:15) is 30 mins slow (wrong by 30). Clock 3 (8:35) is 10 mins slow. The prompt says 'one is slow', which fits 8:35. This satisfies all conditions.

The time difference between 40E and 40W is 80 degrees. Since 15 degrees = 1 hour, 80 degrees = 5 hours 20 minutes. Traveling west, you subtract time. Departure: 2 PM (40E). Local time at 40W then: 8:40 AM. Add 10 hours flight time: 6:40 PM.

The RMS Titanic struck an iceberg at 11:40 PM on April 14, 1912, and foundered (completely sank) at 2:20 AM on April 15, 1912. None of the provided options are perfectly accurate, but 2:45 AM is the closest to the actual time of 2:20 AM.