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# Time Word Problem

In word problems that involve time, you need to think and analyse the problem carefully.

1. Remember that the time is based on 12, not 10. So, we can’t always add or subtract the hour and minutes. Therefore, we count the time.

For example: What would be the time 3 hours after 11:00 AM?

We know that 1 hour later will be 12:00 noon, 2 hours later will be 1:00 PM and 3 hours later will be 2:00 PM. Hence, 3 hours after 11: 00 AM will be 2:00 PM.

2. Remember to include AM/PM.

Let's take a look at some examples:

1. Alfred goes to school at 8:15 AM and comes back home at 3:00 PM. How much time is passed?

Let’s count the time to solve this problem.

Total minutes from 8:15 AM to 9:00 AM = 45 minutes (1 hour = 60 minutes, so 60 – 15 = 45 minutes).

Now, let’s count the hours from 9:00 AM to 3:00 PM

9 - 12 makes 3 hours

12 - 3 makes 3 hours

So, 9 -3 makes 6 hours

6 hours plus 45 minutes

Is this a reasonable amount of time for him to be at school?

Yes it is.

2. It is 7:50 PM and Lydia needs to practice the piano for 30 minutes. What time will it be when she finish her practice?

We need to add 30 minutes to 7:50, but we can’t just add the minutes because we’d get 7:80 and there is no such time.

Total minutes from 7:50 PM to 8:00 PM = 10 minutes (there are 60 minutes in an hour, 60 – 50 = 10)

How much time she will be left with?

30 minutes – 10 minutes = 20 minutes.

She’ll still have 20 minutes left.

What is 20 minutes after 8:00?

It is 8:20.

Yes, if she starts at 7:50 PM and practices for 30 minutes, it makes sense that she’d finish her practice at 8:20 PM.

3. Anton and Titus mowed lawns for 3 hours and 20 minutes. They finished at 1:30 PM. What time did they start?

In this, we need to work backwards to figure out what time they started.

Let’s start by working with the minutes:

What time is 20 minutes before 1:30 PM?

30 – 20 = 10

So, it is 1:10 PM

Now we need to know what is 3 hours before 1:10 PM?

Let’s count backwards:

1 hour before would be 12:10 PM.

2 hours before would be 11:10 AM (We changed it to AM, since the time is before noon).

3 hours before would be 10:10 AM.

Yes, 10:10 AM plus 3 hours and 20 minutes would be 1:30 PM.

Summary

1. Remember that the time is based on 12, not 10. So, we can’t always add or subtract the hour and minutes. Therefore, we count the time.

For example: What would be the time 3 hours after 11:00 AM?

We know that 1 hour later will be 12:00 noon, 2 hours later will be 1:00 PM, and 3 hours later will be 2:00 PM. Hence, 3 hours after 11: 00 AM will be 2:00 PM.

2. Remember to include AM/PM.