## Question

How far does a car travel in 0.75h if it is moving at a constant speed of 88 km/h?

## Answer

**The car covers a distance of 66 kilometres (km) or 66000 metres (m).**

### Explanation

**Data:** The information from the question

The time by which the car covers that distance is, t = 0.75 hours

We also have a constant speed, s = 88 kilometres per hour (km/h)

**Unknown:** What we need to find

distance, x = ?

**Formula:** The equation that will help us solve the problem

Speed (s) = Distance (x) / time (t)

Therefore, we are going to use the formula for speed s=x/t to solve the problem

Don’t forget that the SI unit of distance is in meters. Therefore, we need to convert our final answer into meters.

#### Solution

##### Simple Method

We will use substitute our data into the formula to obtain:

x = s x t = 88 km/h x 0.75 h = (88 x 0.75) km = 66 km

By converting the above answer into metres, we will have: x = 66 km = 66 x 1000 m = 66,000 m

##### Alternative Method (Detail explanation)

From our data, we have time, t equals 0.75 hours

Therefore, if to convert hours into standard international (SI) unit which is second, we will follow the steps below:

Since 1 hour = 1 x 60 x 60 seconds = 3600 seconds

We can now see that

0.75 hours = 0.75 x 60 x 60 seconds = 2700 seconds

Therefore, our time t = 2700 s

Additionally,

The distance from our data is in kilometres per hour. And we need to convert it to a standard international (SI) unit which is metres per second. Thus:

Since 1 km/h = 1 (1000/3600) m/s = 0.2778 m/s

Therefore, 88 km/h = 88 (1000/3600) m/s = 24.44 m/s

**Final calculation**

Now we can solve the distance by applying the values of our speed and time in m/s and s respectively into our formula (s=x/t).

Therefore,

Since we are looking for x, we can easily make it subject of the formula

x = s x t

This implies

x = 24.44 m/s x 2700 s = 66000 m

**Therefore, the distance travelled in meters per second is 66,000 m. And we can also convert it into kilometres by saying that it is (66000 /1000) km to give 66 km.**

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