Step by step
The question
Question: 3/8 room in 3/4 hour: how much is that per hour?
A unit rate says how much for 1 hour.
Per hour means: divide by the hours.
1 Write the rate
Rooms divided by hours: 3/8 ÷ 3/4.
Careful!
Not the other way round.
That would be hours per room.
2 Divide
Dividing by a fraction is the same as times its flip.
Keep the first number.
Change divide to times.
Turn the second fraction upside down.
So 3/4 becomes 4/3, and divide becomes times.
Before we multiply, we make the numbers smaller.
3 on top and 3 at the bottom both divide by 3.
4 on top and 8 at the bottom both divide by 4.
A top and a bottom divided by the same number: the answer stays the same.
So we multiply smaller numbers.
To multiply fractions, we do top times top, and bottom times bottom.
1 times 1 is 1.
2 times 1 is 2.
So the unit rate is 1/2 room per hour.
3 Check
Let's check: 1/2 room per hour, for 3/4 hour.
1/2 times 3/4 is 3/8.
That is the rooms we started with.
So the answer is right!
Let's look back.
First: write the rate.
Then: divide.
Last: check.