Speed, distance, time

Hello, and welcome to Myriora Maths! A train travels a hundred and twenty kilometres in two hours. How fast is it going? Speed, distance and time are all linked. Let's see how.

Speed is how far you go in one hour. A hundred and twenty kilometres in two hours is sixty kilometres in each hour. So the speed is sixty kilometres per hour.

Going the other way: a car drives at fifty kilometres per hour for three hours. Every hour it goes fifty. Three hours: a hundred and fifty kilometres. Distance is speed times time.

Here's a triangle to help you remember. Distance at the top, speed and time at the bottom. Cover the one you want. Speed is distance over time. Time is distance over speed. Distance is speed times time.

How long does it take to cycle thirty kilometres at ten kilometres per hour? Time is distance divided by speed: thirty divided by ten is three hours.

Let's try one together. A bus goes ninety kilometres in three hours. What is its speed? Say it out loud!

Ninety divided by three is thirty. Thirty kilometres per hour!

Here's a question that catches lots of people. A journey takes one hour and thirty minutes. Some people write that as one point three hours. But thirty minutes is half an hour, so it's one point five hours. There are sixty minutes in an hour, not a hundred!

Your turn! A car travels at forty miles per hour for three hours. How far does it go? Pick the right card. You've got twenty seconds, or pause the video. Go!

Time's up! Distance is speed times time. Forty times three is a hundred and twenty miles!

Quick review. Speed is distance divided by time. Distance is speed times time. Time is distance divided by speed. And remember, half an hour is nought point five hours. See you next time!