Year 8 Mathematics | Victorian Curriculum 2.0
Time & time zones
Topic 11 | Measurement & Space | Answer key

Year 8 core - answers

Fluency

Convert and calculate

    1. 16:4516{:}45
    2. 11:0511{:}05 p.m.
    3. 66 h 2525 min
    4. 88 h 2020 min
    5. 3:453{:}45 p.m.
    6. 22:3522{:}35 (previous day)
Fluency

Time zones (standard time)

    1. 12:0012{:}00 noon. Perth is 22 h behind.
    2. 10:0010{:}00 a.m. Brisbane is 3030 min ahead.
    3. 12:0012{:}00 noon. Melbourne is 22 h ahead.
    4. 10:0010{:}00 p.m. (22:0022{:}00). Melbourne is 1010 h ahead.
    5. 7:007{:}00 a.m. next day. Singapore is 1313 h ahead of New York.
Reasoning

Explain and spot the mistake

    1. Not always. In standard time it is 22 h ahead; during daylight saving (October-April for Victoria) it is 33 h ahead because Melbourne shifts to AEDT (UTC+11) while Perth stays on AWST (UTC+8).
    2. A 7−97-9 h westward flight that leaves in the morning can still land on the same day because local time “goes back” 22 h, whereas a late-evening flight crosses the midnight boundary of the arrival zone.
    3. You gain local time on arrival - your watch reads later locally than when you left (the clock runs ahead in local terms). Actually this depends on direction: flying west, local time is earlier, so you arrive at an earlier clock time than your travel hours suggest - effectively gaining hours in your day.
    4. 00:0000{:}00 or 24:0024{:}00 both represent the midnight moment. Most timetables use 00:0000{:}00 as the start of the new day; 24:0024{:}00 is rare.
Problem solving

Real contexts

    1. 7:007{:}00 a.m. Perth time. Method: Perth is 22 h behind Melbourne in April (both standard time).
    2. 08:3008{:}30 AEST next day. Method: arrival in Singapore time =06:30= 06{:}30; add 22 h for AEST.
    3. 99 h total. Method: Melbourne is 3030 min ahead of Adelaide. Bus leaves at 8:458{:}45 Melbourne time; arrives 17:4517{:}45; duration =9= 9 h.
    4. 6:006{:}00 a.m. LA time same day. Method: arrival in Melbourne time =00:00= 00{:}00 next day. Melbourne AEDT is UTC+11; LA is UTC−8-8; LA is 1919 h behind Melbourne. 00:0000{:}00 next day −19- 19 h =05:00= 05{:}00 LA time. Actually: 24:00−19=05:0024{:}00 - 19 = 05{:}00 LA, same calendar day as arrival in Melbourne. Answer: 5:005{:}00 a.m. LA local time on the day of departure.
Year 8 Mathematics study companion | Answer key