Time Management & Time Zones

Video coming soon2 worked examples

Theory

The Golden Rule: When calculating flight arrival times across different time zones, always complete the entire journey using the departure country's time zone first, and only add or subtract the time difference at the very final step.

1. Decimal Time Conversions

You must be completely comfortable converting decimal time to minutes and vice versa.

To convert a decimal to minutes, multiply the decimal part by 60.
(For example, if a flight takes 2.7 hours, $0.7 \times 60 = 42$ , so the time is 2 hours 42 minutes).

2. Time Zones (GMT and UTC)

Countries operate in different time zones depending on their location. A country's time may be given in relation to the UK (e.g., 5 hours behind Edinburgh) or as GMT/UTC (e.g., UTC+2 means 2 hours ahead of the UK).

Ahead: Add the hours on.
Behind: Subtract the hours.

3. Planning Meetings and Overlaps

If you need to find a suitable time for a phone call between two different time zones, draw a timeline for both countries to find the overlapping hours where both people are awake and available.

⚠️ Common Examiner Traps

The "Double Conversion" Trap: Candidates frequently try to change the time zone of the departure time, then add the flight time, then get confused about which time zone they are currently in. Always stick to the starting location's time for the whole journey, and apply the time zone shift right at the end.
The "AM/PM" Trap: you will be penalised for omitting "am" or "pm" from 12-hour times. If you use a 24-hour clock (e.g., 14:15), you do not need am/pm, but 12-hour times must include it.

Worked examples

Example 1

Emma chose to fly from Edinburgh to Alicante. Her plane took off at 11:30 local time.

The time in Alicante is 1 hour ahead of the time in Edinburgh.

The plane flew 1552.5 miles at an average speed of 575 miles per hour.

Calculate the local time that the plane landed in Alicante. (3 marks)

Step 1: Calculate the flight time using $T = D \div S$ .

1552.5 \div 575 = 2.7 \text{ hours}

Step 2: Convert 2.7 hours into hours and minutes.

0.7 \times 60 = 42 \text{ minutes}

The flight is 2 hours 42 minutes.

Step 3: Add the flight time to the departure time (staying in UK time!).

11:30 + \text{2 hours 42 minutes} = 14:12 \text{ (UK Time)}

Step 4: Apply the time zone difference. Alicante is 1 hour ahead.

14:12 + \text{1 hour} = 15:12 \text{ (or 3:12 pm)}

Example 2

Communicating Across Time Zones

Ravi is in Glasgow (GMT). He needs to phone a colleague in Mumbai, where the local time is 5 hours 30 minutes ahead of Glasgow. The colleague is only at their desk between 09:00 and 17:00 Mumbai time.

What is the latest time Ravi can make the call, in Glasgow time?

Step 1: The latest the colleague is available is 17:00 Mumbai time.

Step 2: To convert a Mumbai time back to Glasgow time, subtract the 5 hours 30 minutes difference (because Mumbai is ahead):

17{:}00 - 5\text{ h }30\text{ min} = 11{:}30 \text{ (Glasgow time)}

Answer: Ravi must call no later than 11:30 Glasgow time.

Ready to practise?

11 Time Management and Time Zones questions with answers and video solutions