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Measurement - Calculating time durations across time zones

Grade 4IGCSE

Review the key concepts, formulae, and examples before starting your quiz.

šŸ”‘Concepts

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Understanding Time Zones: The world is divided into different zones where the local time is different based on the position of the sun.

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GMT/UTC: Greenwich Mean Time (GMT) or Universal Coordinated Time (UTC) is the starting point (0) for all time zones.

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East vs. West: Locations to the East are ahead in time (+), while locations to the West are behind in time (-).

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24-Hour Clock: Using 24-hour notation (e.g., 14:00 instead of 2:00 PM) makes calculating durations easier and avoids AM/PM confusion.

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Calculating Duration: To find how long a journey takes across time zones, you must convert both the start time and arrival time to the same time zone first.

šŸ“Formulae

Time in Zone B=Time in Zone A±Time Difference\text{Time in Zone B} = \text{Time in Zone A} \pm \text{Time Difference}

Duration=ArrivalĀ TimeĀ (inĀ ZoneĀ A)āˆ’DepartureĀ TimeĀ (inĀ ZoneĀ A)\text{Duration} = \text{Arrival Time (in Zone A)} - \text{Departure Time (in Zone A)}

1Ā hour=60Ā minutes1 \text{ hour} = 60 \text{ minutes}

šŸ’”Examples

Problem 1:

London is at GMT+0 and Dubai is at GMT+4. If a plane leaves London at 09:00 and the flight takes 7 hours, what is the local time in Dubai when it lands?

Solution:

20:00 (or 8:00 PM)

Explanation:

First, find the arrival time in London time: 09:00 + 7 hours = 16:00. Then, convert London time to Dubai time by adding the 4-hour difference: 16:00 + 4 hours = 20:00.

Problem 2:

New York is GMT-5. If it is 10:00 AM in London (GMT+0), what time is it in New York?

Solution:

05:00 AM

Explanation:

Because New York is GMT-5, it is 5 hours behind London. Subtract 5 hours from 10:00 AM: 10 - 5 = 5. So, it is 05:00 AM.

Problem 3:

A flight leaves Paris (GMT+1) at 14:00 and arrives in Tokyo (GMT+9) at 08:00 the next day. How long was the flight?

Solution:

10 hours

Explanation:

First, convert the Tokyo arrival time to Paris time. Tokyo is 8 hours ahead of Paris (9 - 1 = 8). If it is 08:00 in Tokyo, subtract 8 hours to get Paris time, which is 00:00 (midnight). Now calculate the duration from 14:00 to 00:00. From 14:00 to 24:00 is 10 hours.