Home

Maths

Rates of change

Reading timetables

Reading timetables

Select Lesson

Proportion


Ratio


Explainer Video

Loading...
Tutor: Labib

Summary

Reading timetables 

​​In a nutshell

Timetables are used in many places in society. They are a useful and organised way of displaying schedules.



The 12 and 24 hour time system

Time is represented in two main formats: the 1212​ hour system and the 2424​ hour system.


12 hour system

24 hour system

  • Only uses numbers from 11​ to 1212​ to describe the hour.
  • Uses amam​ to refer to the time from midnight to 11:5911{:}59​ in the morning and pmpm​ to refer to the time from midday to 11:5911{:}59​ in the evening.
  • Uses numbers from 0000​ to 2323​ to describe the hour.
  • 0000​ is midnight.
  • Hour is always 22​ digits (so 55​ is written as 0505​).


​​Converting between the 12 and 24 hour formats

converting from 12 hour to 24 hour

Converting from 24 hour to 12 hour

  • If the hour is between 1am1am​ and 11am11am: get rid of the amam​.
  • If the hour is between 1pm1pm​ and 11pm11pm​: add 1212​ to the hour, get rid of the pmpm​.
  • If the time is between 12am12am​ and 12:59am12{:}59am: subtract 1212​ and get rid of the amam​.
  • If the time is between 12pm12pm​ and 12:59pm12{:}59pm: get rid of the pmpm​.
  • If the hour is between 11 and 1111​: add an amam​.
  • If the hour is between 1313​ and 23:23{:} subtract 1212​ from the hour, add a pmpm​.
  • If the time is between 00:0000{:}00​ and 00:5900{:}59: add 1212​ and add an amam​.
  • If the time is between 12:0012{:}00​ and 12:5912{:}59: add a pmpm​.


Examples
  • 6:30pm6{:}30pm​ is 18:3018{:}30​ in the 2424​ hour format.
  • 05:2205{:}22​ is 5:22am5{:}22am​ in the 1212​ hour format.
  • 12:55am12{:}55am is 00:5500{:}55in the 2424​ hour format.
  • 12:1212{:}12​ is 12:12pm12{:}12pmin the 1212​ hour format.



Adding and subtracting times

When adding and subtracting times, always remember that there are 6060​ minutes in an hour.


Example 1

How much time passes from 1:30pm1{:}30pm​ to 5:15pm5{:}15pm​?


First, find how much time is needed to get to the next hour:

The next hour is 2pm2pm​. To get to 2pm2pm​, you have to add 30\textbf{30}​ minutes to 1:30pm1{:}30pm​.


Then, find how much time is needed to get to 5pm5pm​:

From 2pm2pm​ to 5pm5pm​, you have to add 52=35-2=\textbf{3}hours.


Find how much time is needed to get to 5:15pm5{:}15pm​:

From 5pm5pm​ to 5:15pm5{:}15pm​, you have to add 15\textbf{15}​ minutes.


Add all the times together: 

3030minutes + 33 hours + 1515 minutes = 33 hours + 4545 minutes.


3 hours and 45 minutes\underline{3 \ \text{hours\ and} \ 45 \ \text{minutes}} passes from 1:30pm1{:}30pm to 5:15pm{5{:}15pm}



Timetables

Timetables are used to organise schedules. They are often used in bus and train stations and they tend to use the 2424​ hour time format.


Example 2

In the train timetable given, assume all trains take the same amount of time to make the same journey.

i) Find the values of XX​ and YY​.

ii) A family is at Cambridge and wants to arrive at Paddington before 2:30pm2{:}30pm. What is the latest train they can take?


station

arrival times

train a

train b

train c

Cambridge

11:0211{:}02​​

12:1512{:}15​​

YY​​

Tottenham

12:2712{:}27​​

XX​​

14:3714{:}37​​

Paddington

13:0013{:}00​​

14:1314{:}13​​

15:1015{:}10​​

Surrey

14:0514{:}05​​

15:1815{:}18​​

16:1516{:}15​​


Part i)

The time it takes for the trains to go from Cambridge to Tottenham is always the same. 

So, to find XX​ and YY, first find how long it takes Train A to go from Cambridge to Tottenham:

This is the same as finding the time from 11:0211{:}02 to 12:2712{:}27:

11:0211{:}02to 12:0012{:}00: + 58+\,\textbf{58} minutes


12:0012{:}00to 12:2712{:}27: + 27+\,\textbf{27} minutes


So, the time it takes to go from Cambridge to Tottenham is:

58+27=8558+27=85minutes


Convert this to minutes and hours:

8585minutes =1=1 hour and 2525 minutes


Add this time onto 12:1512{:}15 to find the value of XX:

12:15+112{:}15+1hour + 25+\,25 minutes =X=X


13:15+2513{:}15+25​​​ minutes =X=X

X=13:40\underline{X=13{:}40}


To find YY, subtract 11 hour and 2525 minutes from 14:3714{:}37:

14:37114{:}37-1 hour 25-\,25 minutes =Y=Y


13:372513{:}37-25 minutes =Y=Y

Y=13:12\underline{Y=13{:}12}


Part ii)

First, convert 2:30pm2{:}30pm to the 2424​ hour format:

2:30pm=14:302{:}30pm=14{:}30​​


Look at the timetable to find the latest train that arrives at Paddington before 14:3014{:}30:

The latest train that arrives at Paddington before 14:3014{:}30 arrives at 14:1314{:}13.

This corresponds to the 12:1512{:}15 train at Cambridge.


The latest train that the family can take is train B.


Create an account to read the summary

Exercises

Create an account to complete the exercises

FAQs - Frequently Asked Questions

How do you read timetables?

How do you convert between 12 hour and 24 hour times?

What are the two main formats of time?

Beta

I'm Vulpy, your AI study buddy! Let's study together.