What is 'Elapsed Time’?
The elapsed time of an event is the amount of time that has passed between the commencement and the completion of an event. If an event starts at noon and ends at 2 o’clock, the elapsed time is the time that has passed between noon and 2 o’clock, which is 2 hours. But it may not always be this simple to calculate the elapsed time of events as they can start and end at any time. We will learn a simple technique that helps us find the elapsed time of events easily.
How do we Calculate the Elapsed Time of Events?
To find the elapsed time of events, we need to subtract the start time of the event from the end time. We need to subtract seconds, minutes, hours, and sometimes days, separately to calculate the elapsed time of events. The formula to find the elapsed time is as follows:
Elapsed time = End time – Start time
[Note: When subtracting start time from end time, express both times in the 24 hour format for easy calculation.]
Solved Examples
Example 1: If an event starts at 8:00 AM and ends at 10:00 AM, find the elapsed time of the event.
Solution:
The elapsed time of the event is the time between 8:00 AM and 10:00 AM. To find the time between the start time and the end time, we need to subtract the start time from the end time.
So, Elapsed time = End time – Start time
Elapsed time = 10:00 – 8:00
Elapsed time = 2:00 or 2 hours
Therefore, the event went on for 2 hours.
Example 2: An event starts at 9:00 AM and ends at 11:30 PM. Find the elapsed time of this event.
Solution:
Start time of the event: 9:00 AM
End time of the event: 11:30 PM
But here, the start time is in AM, and the end time is in PM. It is easier to find the elapsed time if we convert these times into the 24-hour format.
In the 24-hour format, 9:00 AM is 9:00, and 11:30 PM is the same as 23:30.
So, start time of the event: 9:00
End time of the event: 23:30
We know that Elapsed time = End time – Start time
23:30 – 9:00
∴ Elapsed time = 14:30 or 14 hours and 30 minutes
So, the elapsed time of the event is 14 hours and 30 minutes.
Example 3: A court hearing starts at 8:15 AM and ends at 1:45 PM. If there was a recess between 12:00 and 12:10, find the elapsed time of the hearing.
Solution:
Start time of the court hearing: 8:15 AM
End time of the court hearing: 1:45 PM
Since the start time is in AM and the end time is in PM, we need to convert them into the 24-hour format for easy calculation.
Hence, start time of the court hearing: 8:15
End time of the court hearing: 13:45
Total Elapsed time = End time – Start time
13:45 – 8:15
∴ Total Elapsed time = 5:30 or 5 hours and 30 minutes
Since there was a recess between 12:00 and 12:10, we need to subtract the elapsed time of the recess from the total elapsed time to find the time elapsed while the hearing was in progress.
Elapsed time of recess = Recess end time – Recess start time
12:10 – 12:00
∴ Elapsed time of recess = 0:10 or 10 minutes
Hence, Elapsed time of hearing = Total elapsed time – Elapsed time of recess
5:30 – 0:10
∴ Elapsed time of the hearing = 5:20 or 5 hours and 20 minutes
Hence, the court hearing went on for 5 hours and 20 minutes.
The elapsed time of an event is the time duration between the beginning and the end of the event.
Yes, we can calculate the elapsed time of events that last multiple days by subtracting the days along with hours, minutes, and seconds.
We use the concept of elapsed time to find the time we spend on studies, entertainment, sleep, and so on.