This document provides examples of solving time-related problems by converting between hours and minutes. It gives step-by-step workings for converting times such as 6.15 hours to hours and minutes, finding the number of minutes in periods like 3 hours and 1/4 hours, and converting total minutes to hours and minutes. Examples are also given for calculating elapsed time between times on different days and the total time taken by adding periods spent on different days.

1. Chapter 10G – Time – Worked Solutions
Example One
What is 6.15 hours in hours and minutes?
0.15 minutes
= 0.15 × 60 = 9
Therefore, 6.15 hours is the same as 6 hours and 9 minutes
Example Two
How many minutes are there in each of the following periods?
3
1
4
hours
1
4
=25mins
=3 hours 25mins
Example Three
Change the following to hours and minutes.
230 minutes
230 ÷ 60
3 remainder 50
∴230mins = 3 hours and 50 mins
Example Four
Change the following to minutes.
16
3
4
hours
= (16 × 60)+ 45mins
Ans = 1045minutes
Example Five
How many minutes in a year?
365 days × 24 hours × 60 minutes
Ans = 525600 minutes

2. Chapter 10G – Time – Worked Solutions
Example Six – Elapsed Time
What is the time 1 hour and 10 minutes before 11.30am?
Use a T-Table breaking it up into smaller time segments.
Elapsed Time Time
Current time 11.30am
1 hour before 10.30am
10 minutes before 10.20am
Example Seven – Elapsed Time
Find the time difference between 1.20 pm on Wednesday and 9.09 am the following
Friday.
Elapsed Time Time
Current time 1.20pm Wednesday
24 hours – 1 day 1.20pm Thursday
12 hours 1.20am Friday
8 hours 9.20am
- 11 minutes 9.09am
Add up all the elapsed times
1 day 20 hours take away 11 minutes
Answer: 1 day 19 hours 49 minutees
Alternative solution
or (24 + 19) + (60 - 11)
Answer = 43 hours and 49 minutes

3. Chapter 10G – Time – Worked Solutions
Question 23 – Problem solving
If James spends 35 minutes on Friday, 2 hours and 12 minutes on Saturday and
1.25 hours on Sunday to complete his assignment, how much time did he take
altogether?
35 + 132 + (60 + 15) = 167 minutes + 75 minutes = 242 minutes
In hours and minutes it is written like this:
242 ÷ 60
4 hours and 2 minutes
To get the answer you type in 242 ÷ 60 (how many minutes in an hour)
This gives you 4.03. Therefore 4 × 60 = 240 with 2 remainder,
Hence giving you the soution of 4 hours and 2 minutes.