Time 12 And 24 Hour Clock
Time – Introduction
In this article we are going to look at questions that involve time. You need to be able to do various conversions such as changing minutes to seconds and hours to minutes for instance.
You will also need to know how to calculate differences in times that are given in fraction form or even decimals.
TIme - Short Questions
To answer this question you need to know that 1 hour = 60 minutes. So to do this you are dividing by 60.
\frac{120}{60}The answer is 2 hours
Here you need to recognise that \frac{3}{4} hours is equivalent to 45 minutes.
So you are working out the difference between 55 minutes and 1 hour 45 minutes.
Probably the easiest method is to consider the difference between 55 minutes and 1 hour 55 minutes. This would be 1 hour or 60 minutes. But because we added 10 minutes, this now needs to be subtracted from 60 minutes, to give a final answer of 50 minutes.
TIme - Long Questions
Questions like this are actually quite common and you need to deal with each sentence at a time. Whatever you do, do not let the amount of wording put you off.
Let us take a look at the question and work through it step by step.
Leave home: 10:40am + 14 minutes walk to shop = 10:54am
At the shop for 10 minutes = 10:54am + 10 minutes = 11:04am
Walk to a friend’s house = 11:04am + 22 minutes = 11:26am and this is the final answer.
There are a number of ways to do this type of question. One way is to add 15 minutes from the 98 minutes to get to 8pm. There are still 83 minutes to add which is one hour and 23 minutes. So this would mean that the film would finish at 9:23pm. And this is the final answer.
Time – Mixed Units
This question is worth only 2 marks but some working out needs to be done to get those two marks. Again, it is best to just work through each sentence and to add the increases in time as you go along.
Leave home at 9:15am + 2 hours 15 min minutes = 11:30 am
Break for 20 minutes = 11:30 am + 20 minutes = 11:50am
Drive for another 85 minutes (which is one hour 25 minutes) + 11:50 am + 1 hour 15 minutes = 13:15 and this is the correct answer.
You could also have written the answer as 1:15pm. There is no need to have an answer in 12 hour or 24 hour clock form unless a question wants it, so just make sure you know what a question is asking for.
Time – Timetables
Here you need to read the timetable. Looking at the timetable the train leaves St Pancras at 0618 and arrives at Paris at 0947. You are finding the difference between these times.
47 minutes – 18 minutes = 29 minutes
9 hours – 6 hours = 3 hours
So the total time is 3 hours and 29 minutes.
For this question you are actually asked to give the answer in minutes, so you need to be ready to convert.
3 hours = 180 minutes, so 180 + 29 = 209 minutes
First find the time of arrival and the duration for each journey.
The 0540 arrives at 0917 which is a duration of 217 minutes = 3 hours 37 minutes
The 0618 arrives at 0947 which is a duration of 209 minutes = 3 hours 29 minutes
So the difference in minutes is 217 – 209 = 8 minutes.
Georgie would have to catch the 0655. The dashes in the timetable means that there is no train at those times.
Time – Long Timetables
Again this is a case of reading the timetable. You need to find the correct times, the station that it has left and the destination. So if the train leaves at 1440 then it will arrive at Birmingham Moor Street at 1632
The 1410 arrives at 1556. You can simply subtract the minutes and hours which will give 1 hour and 46 minutes.
The question has asked for the answer to be in minutes so you need to be ready to convert. 1 hour = 60 minutes so the total time is 60 + 46 = 106 minutes.
Like similar previous questions to this deal with one sentence at a time.
If she leaves home at 3:15pm then she has to catch the 1541 train. Which arrives at the destination at 1632. Then you need to add the 20 minutes that it takes to get to her meeting so she will arrive at 1652. So yes she will be on time.
One thing that you need to be careful about with this question is that the question gives the times in terms of 12 hour clock notation but the timetable is in 24 hour clock notation. So it is important that you are able to convert between 12 and 24 hour clock form.