Step by step
The question
Question: A cyclist rides at 18 km/h.
How many hours does it take to ride 63 km?
1 Find what we know
What do we know?
The cyclist goes 18 km in each hour.
The trip is 63 km.
What do we want?
How many hours.
2 Name the unknown
We don't know how many hours.
So we call it x.
How far we go: speed times time.
18 km/h means 18 km in each hour.
Let's draw it.
The cyclist starts here.
It goes 18 km in each hour, for x hours.
The whole trip: 63 km.
3 Write the equation
In words: speed times time makes the distance.
So the equation is 18x = 63.
Now we solve it.
Is x alone now?
Not yet: 18x means 18 times x.
How do we remove it?
4 Remove the 18
To remove times 18, we divide by 18.
We do it on both sides, so they stay equal.
18 divided by 18 is 1.
They cancel each other.
So just x is left.
We can make 63/18 simpler.
It is the same as 7/2.
So x = 7/2.
5 Answer the question
7/2 is 3.5.
So it takes 3.5 hours.
6 Check
Let's check in the story.
3.5 hours at 18 km/h: 3.5 times 18 is 63 km, like the story says.
Check it with the picture.
The cyclist drives 3.5 hours at 18 km/h: 63 km, the whole trip.
So the answer is right!
Let's look back.
First: find what we know.
Then: name the unknown.
Then: write the equation.
Then: solve it.
Then: answer the question.
Last: check.