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YEAR 8 · TIME AND TIME ZONES · 18 MIN

Checking real-world scheduling answers

Check travel schedules by putting times on one clock, including journey duration and transfer rules.

In this lesson

Before you start
  • Calculate durations and timetable gaps.
  • Convert times using stated UTC offsets.
01 / LEARN

Understand the idea.

Convert before subtracting

Travel duration measures time passing, while an offset measures a difference between clocks. Put departure and arrival on the same clock before subtracting. Retain their dates as well, especially if a journey or conversion crosses midnight.

For a departure at 10:40 in UTC+2 and arrival at 16:10 in UTC+5, the local readings appear 5 hours 30 minutes apart. Three hours of that gap are a zone difference; the traveller has experienced only 2 hours 30 minutes.

Build a feasible schedule

To predict arrival, convert departure to UTC, add the travel duration, then convert to the destination clock. A schedule is feasible only when every stated transfer, check-in and timing condition is also met.

Check the meaning of the result. An arrival clock reading earlier than departure can be valid after travelling west, but the elapsed interval on one dated reference clock must stay positive. Reverse the calculation to check both duration and local day.

02 / WORKED EXAMPLES

See the method in action.

EXAMPLE 01

Find a flight duration

A flight leaves at 10:40 from UTC+2 and arrives at 16:10 in UTC+5 on the same local day. Find its duration.

Worked solution

  1. 1

    Convert departure to UTC.

    10:40−2 h=08:40 UTC

    Subtracting the origin's positive offset removes its clock advance.

  2. 2

    Convert arrival to UTC.

    16:10−5 h=11:10 UTC

    The destination reading needs its own offset removed.

  3. 3

    Measure the interval on the shared clock.

    08:40 to 11:10=2 h 30 min

    Both UTC readings are on the same day, so this is the flight duration.

Answer

2 h 30 min.

EXAMPLE 02

Predict arrival

A flight leaves at 11:25 from UTC+9:30 and lasts 2 h 45 min. Give the arrival time in a town at UTC+8.

Worked solution

  1. 1

    Convert the departure to UTC.

    11:25−9 h 30 min=01:55 UTC

    UTC is nine hours thirty minutes behind the departure clock.

  2. 2

    Add the time spent flying.

    01:55+2 h 45 min=04:40 UTC

    Duration is added on one reference clock.

  3. 3

    Apply the destination offset.

    04:40+8 h=12:40

    The destination is eight hours ahead of UTC; neither conversion crosses a date boundary.

  4. 4

    Check using the offset difference.

    11:25+2 h 45 min−1 h 30 min=12:40 same day

    The destination clock is one hour thirty minutes behind the origin clock.

Answer

12:40, on the same day.

03 / YOUR TURN

Try it yourself.

Check your understanding

A 2-hour flight departs UTC+3 at 09:00. What is arrival time at UTC+1?

Show answer & reasoning

09:00, on the same day.

09:00 at UTC+3 is 06:00 UTC. After 2 hours it is 08:00 UTC, which is 09:00 at UTC+1 on the same day. Matching local readings do not mean zero travel time.

Keep practising

6 worksheet questions · 12 marks

Open worksheet Worked solutions
Read the questions online
  1. A trip departs 08:30 at UTC+2 and arrives 13:00 at UTC+4 on the same day. Find its duration.
    2 marks
  2. A 3-hour flight leaves 14:20 at UTC+5. Give arrival time at UTC+2.
    2 marks
  3. A 2 h 20 min flight leaves 22:50 Friday at UTC+1. Find arrival at UTC+3.
    2 marks
  4. A plane lands at 10:15. The next flight leaves 11:05, and the minimum connection is 55 min. Does it work?
    2 marks
  5. A 90-minute trip leaves at 23:20 Tuesday in one zone. The destination is 2 hours behind. Give arrival day/time.
    2 marks
  6. Local departure is 12:00 at UTC+4. Local arrival is 14:00 at UTC+1 on the same day. A student claims the journey took 2 hours. Check the claim.
    2 marks
Read the worked solutions

Equivalent correct methods earn the corresponding marks. Include units where asked.

  1. A trip departs 08:30 at UTC+2 and arrives 13:00 at UTC+4 on the same day. Find its duration.
    2 marks

    UTC departure 06:30; UTC arrival 09:00.

    Difference=2 h 30 min.

    2 h 30 min.
  2. A 3-hour flight leaves 14:20 at UTC+5. Give arrival time at UTC+2.
    2 marks

    Departure is 09:20 UTC. Add 3 h to get 12:20 UTC. Add 2 h for the destination: 14:20.

    14:20, same day.
  3. A 2 h 20 min flight leaves 22:50 Friday at UTC+1. Find arrival at UTC+3.
    2 marks

    Departure is 21:50 Friday UTC. After 2 h 20 min it is 00:10 Saturday UTC. Add 3 h for the destination: 03:10 Saturday.

    Saturday 03:10.
  4. A plane lands at 10:15. The next flight leaves 11:05, and the minimum connection is 55 min. Does it work?
    2 marks

    11:05−10:15=50 min<55 min.

    No; only 50 min is available, 5 min short.
  5. A 90-minute trip leaves at 23:20 Tuesday in one zone. The destination is 2 hours behind. Give arrival day/time.
    2 marks

    On the origin clock, arrival is Wednesday 00:50.

    Subtract 2 h for the destination: Tuesday 22:50.

    Tuesday 22:50.
  6. Local departure is 12:00 at UTC+4. Local arrival is 14:00 at UTC+1 on the same day. A student claims the journey took 2 hours. Check the claim.
    2 marks

    Departure is 08:00 UTC; arrival is 13:00 UTC.

    13:00−08:00=5 h.

    It took 5 hours, not 2.
Checking saved progress…
Curriculum reference & lesson scope

Australian Curriculum v9 and SA Curriculum Mathematics

Converting 12-/24-hour time; elapsed time across midnight; timetables and journeys; time-zone differences; date changes; checking real-world scheduling answers.

Official curriculum source ↗

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