# 3.2 Converting units of time

You can see from the diagram below that to convert units of time you can use a very similar method to the one you used when converting other units of measure. There is one slight difference when working with time however.

Let’s say you want to work out how long 245 minutes is in hours. The diagram above shows that you should do 245 ÷ 60 = 4.083. This is not a particularly helpful answer since you really want the answer in the format of: ___ hours __ minutes. Due to the fact that time does not work in 10s, you need to do a little more work once arriving at your answer of 4.083.

The answer is obviously 4 hours and an amount of minutes.

4 hours then is 4 × 60 = 240 minutes.

Since you wanted to know how long 245 minutes is you just do 245 – 240 = 5 minutes left over. So 245 minutes is 4 hours and 5 minutes.

It’s a very similar process if you want to go from say minutes to seconds. Let’s take it you want to know how long 5 minutes and 17 seconds is in seconds. 5 minutes would be 5 × 60 = 300 seconds. You then have a further 17 seconds to add on so you do 300 + 17 = 317 seconds.

Have a go at the activity below to make sure you feel confident with converting times.

## Activity 7: Converting times

Convert the following times:

- 6 hours and 35 minutes = ___ minutes.
- 85 minutes = ____ hours and ____ minutes.
- 153 seconds = ____ minutes and ___ seconds.
- 46 days = ___ weeks and ____days.
- 3 minutes and 40 seconds = ____ seconds.

### Answer

6 hours = 6 × 60 = 360 minutes

360 minutes + 35 minutes = 395 minutes

85 minutes ÷ 60 = 1.417 (rounded to three d.p)

1 hour = 60 minutes.

85 minutes − 60 minutes = 25 minutes remaining

So 85 minutes = 1 hour and 25 minutes

153 seconds ÷ 60 = 2.55

2 minutes = 2 × 60 = 120 seconds

153 seconds − 120 seconds = 33 seconds remaining

So 153 seconds = 2 minutes and 33 seconds

46 days ÷ 7 = 6.571 (rounded to three d.p)

6 weeks = 6 × 7 = 42 days

46 days − 42 days = 4 days remaining

So 46 days = 6 weeks and 4 days

3 minutes = 3 × 60 = 180 seconds

180 seconds + 40 seconds = 220 seconds

Hopefully you found that activity fairly straightforward and are now feeling ready to move on to the next part of the ‘Units of measure’ session – Average speed.