Time, timetables and time zones questions with answers

Questions

1. Question 112-hour and 24-hour clock

   A concert ends at 5.45 p.m. Write down this time using the 24-hour clock.

   Show the worked solution

   1. Step 1: p.m. is after noon: add 12 to the hour$5 + 12 = 17$So 5.45 p.m. is 1745, with 4 digits (45 minutes).
2. Question 2How long, including past midnight

   A movie marathon starts at 1650 and ends at 2255 the same day. Find the duration of the movie marathon, in hours and minutes.

   Show the worked solution

   1. Step 1: Time taken = end time − start time$22 \text{ h } 55 \text{ min} - 16 \text{ h } 50 \text{ min}$$= 6 \text{ h } 5 \text{ min}$It takes 6 h 5 min.
3. Question 3Reading a bus timetable

   The table shows part of a bus timetable. Ben reaches the Interchange stop at 1857 and takes the first bus that comes. Find the total time, in minutes, that Ben takes from reaching the Interchange stop to arriving at the Library stop.

   Bus stop	Bus 1	Bus 2	Bus 3	Bus 4	Bus 5
   Interchange	1830	1844	1900	1917	1935
   Market	1837	1851	1907	1924	1942
   Library	1845	1859	1915	1932	1950
   Polyclinic	1856	1910	1926	1943	2001
   Stadium	1908	1922	1938	1955	2013

   Show the worked solution

   1. Step 1: The first bus at the Interchange stop at or after 1857Bus 3 (at the Interchange stop at 1900).
   2. Step 2: From reaching the Interchange stop to arriving at the Library stop: subtract the times$19 \text{ h } 15 \text{ min} = 18 \text{ h } 75 \text{ min} \quad (1 \text{ h} = 60 \text{ min})$$18 \text{ h } 75 \text{ min} - 18 \text{ h } 57 \text{ min}$$= 0 \text{ h } 18 \text{ min}$It takes 18 minutes altogether.
4. Question 4Local time in another time zone

   The table shows the time differences between Singapore and some cities. Siti in Singapore plans to call a friend in Tokyo at 1010 on 20 May, Tokyo time. Find the time and date in Singapore when the call is made.

   City	Time compared with Singapore
   Paris	6 h behind Singapore
   Tokyo	1 h ahead of Singapore
   Auckland	4 h ahead of Singapore

   Show the worked solution

   1. Step 1: From the table: how far ahead or behind SingaporeTokyo is 1 h ahead of Singapore.
   2. Step 2: Change to Singapore time: add or take away the differenceIt stays on the same day.
   3. Step 3: Take it away$10 \text{ h } 10 \text{ min} - 1 \text{ h}$$= 9 \text{ h } 10 \text{ min}$
   4. Step 4: Check the date: past midnight is the next day, before midnight the day beforeTime in Singapore: 0910 on 20 May.
5. Question 5When a flight lands, in local time

   The table shows the time differences between Singapore and some cities. A flight leaves Seoul at 1240 on 16 May, Seoul time. The flight takes 6 h 25 min. Find the local time and date when it lands in Singapore.

   City	Time compared with Singapore
   Dubai	4 h behind Singapore
   Seoul	1 h ahead of Singapore
   New York	12 h behind Singapore

   Show the worked solution

   1. Step 1: Landing time in Seoul time: departure time + flight time$12 \text{ h } 40 \text{ min} + 6 \text{ h } 25 \text{ min}$$= 18 \text{ h } 65 \text{ min}$$= 19 \text{ h } 5 \text{ min} \quad (60 \text{ min} = 1 \text{ h})$
   2. Step 2: From the table: how far ahead or behind SingaporeSeoul is 1 h ahead of Singapore.
   3. Step 3: Change to Singapore time: add or take away the differenceIt stays on the same day.
   4. Step 4: Take it away$19 \text{ h } 5 \text{ min} - 1 \text{ h}$$= 18 \text{ h } 5 \text{ min}$
   5. Step 5: Check the date: count each midnight passedLands in Singapore: 1805 on 16 May.
6. Question 6The latest departure to arrive in time

   The table shows the time differences between Singapore and some cities. Devi has a meeting in Singapore at 1400 on 19 May. The flight from Seoul takes 6 h 20 min, and getting from Changi Airport to the meeting takes 50 min. Find the latest time and date, in Seoul time, at which the flight can leave Seoul.

   City	Time compared with Singapore
   Dubai	4 h behind Singapore
   Seoul	1 h ahead of Singapore
   New York	12 h behind Singapore

   Show the worked solution

   1. Step 1: Latest landing time, in Singapore time: the meeting time − the journey from the airport$14 \text{ h } 0 \text{ min} = 13 \text{ h } 60 \text{ min} \quad (1 \text{ h} = 60 \text{ min})$$13 \text{ h } 60 \text{ min} - 0 \text{ h } 50 \text{ min}$$= 13 \text{ h } 10 \text{ min}$
   2. Step 2: Latest take-off time, in Singapore time: take away the flight timeIt stays on the same day.
   3. Step 3: Take it away$13 \text{ h } 10 \text{ min} = 12 \text{ h } 70 \text{ min} \quad (1 \text{ h} = 60 \text{ min})$$12 \text{ h } 70 \text{ min} - 6 \text{ h } 20 \text{ min}$$= 6 \text{ h } 50 \text{ min}$
   4. Step 4: From the table: how far ahead or behind SingaporeSeoul is 1 h ahead of Singapore.
   5. Step 5: Change to Seoul time: add or take away the difference$6 \text{ h } 50 \text{ min} + 1 \text{ h}$$= 7 \text{ h } 50 \text{ min}$
   6. Step 6: Check the date: count each midnight passedLatest departure, Seoul time: 0750 on 19 May.