Functional Skills: Speed

Example 1: Calculating Speed

A car travels $30$ km in $48$ minutes. Calculate the average speed of the journey in km/h.

[2 marks]

First convert $48$ minutes into hours: $48$ minutes $=dfrac{48}{60}$ hours $=0.8$ hours

Then calculate the average speed: $text{Speed} = dfrac{text{Distance}}{text{Time}}=dfrac{30}{0.8}=37.5$ km/h

Example 2: Calculating Distance

A cyclist travels at an average speed of $14$ mph for $25$ minutes. Calculate how far the cyclist travelled, give your answer to $2$ decimal places.

[2 marks]

Using the speed, distance and time triangle we can see that:  distance $=$ speed $times$ time.

So the distance travelled by the cyclist $=14times dfrac{25}{60}=5.83$ miles

Note: You often need to convert minutes into hours.

Example 3: Calculating Time

A plane is going from Manchester to Madrid, which is a $1292$ mile journey.

The plane travels at an average speed of $516.8$ mph, calculate the time taken for this flight, giving your answer in hours and minutes.

[2 marks]

Using the speed, distance and time triangle we can see that:  $text{time} = dfrac{text{distance}}{text{speed}}$

So the time taken for the journey $=dfrac{1292}{516.8}=2.5$ hours $=2$ hours and $30$ minutes