This is a favourite exam question. Converting miles to kilometres can also make the journey seem longer (!).
This series of 3 minute math is designed as a quick reminder for some of the main topics. I hope they help to provide a focus and a way forward. If you need any more detail please search the site or contact me – always pleased to answer any questions!
All the very best with your studies.
Kilometres and miles are both units of distance. In the UK and USA we tend to use miles. In many other countries the metric system of kilometres (sometimes spelled kilometers) is used, and you might sometimes be asked about converting miles to kilometres – particularly in exam questions.
Video Transcript:
“Welcome to 3 Minute Maths. In this particular video, we’re going to be looking at converting miles to kilometers. A typical question would go something like this:
‘Somebody is driving their car and at 60 mph. How long will it take them to drive 120 km?’
The difficulty here is that you got ‘mph’ then ‘km,’ so it’s a different unit. You need to know that 8 mi = 5 km. So, if you remember that, it’s really useful because if we’re driving at 60 mph, we can find out how many ‘lots of 5 mph’ that are in 60.
So, we’ve got 60 mph and need to find how many lots of 5 mph. Once that has been calculated we can multiply by 8 and that will give us how many kilometers are equivalent to 60 mph.
What I mean by that is this: if I got 60, I’m going to divide that by 5. And, 60/5 tells me that it’s 12 lots – so, 12 lots of 5 mph blocks. Multiply that by 8 and I’m going to get 96. So, 96 km/h is exactly the same as 60 mph.
Then, all I’ll simply do is use Speed = 
.
And, again, this is a really important formula that you need to remember. What it allows me to do is to feed some of this information in and it’ll tell me how long it takes to drive 120 km.
My speed is going to be 60 mph but, actually, I need it in the same unit so it’s going to be 96. And, that’s going to be a distance of 120 km, which I’ve been given in the question, and the T is going to be below it.
96 = 120/T
So, if I use just a little bit of algebraic manipulation, I get the time as equaling the same as 120 divided by 96.
T = 120/96
120 divided by 96 is going to be 1 1/4. And, that’s going to be 1 1/4/ hours to drive 120 km at an average speed of 60 mph or its direct equivalent, 96 km/h.
I hope that’s okay. That’s 3 Minute Maths. I’ll look forward to seeing you in the next video.”
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